In case you missed it, recently Xbox Cloud Gaming (which from here onwards I will refer to as "XCloud") became available as a part of Xbox Game Pass Ultimate on Mexico and Brazil, the latter of which finally allowed me to check out the service since before there were no servers at all in South America. I upgraded my GP sub to Ultimate once it released and have been using it quite a bit over the past few weeks, here's how my experience with the service has been:
QUALITY:
The main thing about all gaming streaming services will always be image quality and latency. In my experience with XCloud, you could describe it as "good enough" - the latency is slightly noticeable, and the image quality is also not as good as native, but they are at least on a level where you can enjoy the game without it being annoying. It also depends heavily on what device you're playing on how noticeable it is, since for example on my PC it's often pretty clear that you're just watching a video, but on my phone or on a TV it masks all the compression artifacts really well. I've tried a variety of games on it and personally, I didn't have any trouble enjoying any of them including shooters, racing games or fast-paced platformers like Celeste. While the IQ and latency could improve as I've already said, the games themselves all had great performance and really quick loading times since iirc the servers are now being powered by Series-equivalent hardware.
EASE OF USE:
The main thing XCloud has over services like Stadia or Geforce Now, is its ease of use since by just subbing to Game Pass Ultimate, you gain access to all the cloud games that are available on the service, which at the time of writing this is a bit more than 300 games. If there's one thing Microsoft deserves props for though, is just how seamless the whole proccess is. You just open the mobile or PC apps, or even just the XCloud site in your preferred web browser, log into your account, connect a controller (including a DS4! didn't expect it to work without tweaks) if you need it and... that's it, you don't have to worry about network tests, adjusting settings, managing savefiles, updating or downloading games, etc. It's about as close to a "it just works" experience as you can get.
To give you an example, my most played Game Pass game is probably Forza Horizon 4, which I used to play the PC version of. However, since the preload for Horizon 5 was just enabled the other day and it's pretty huge in terms of gigabytes, I had to make room for it and there was no more obvious candidate for deletion than the game it will be replacing in my gaming time. As it's quite natural, once the release date of FH5 loomed closer, I felt an itch to play another Forza Horizon game again but I really didn't want to have 250GB on my PC dedicated to Forza Horizon games, but all I had to do to keep playing was click on the "Cloud Gaming" tab instead of the usual one, select Forza Horizon 4 and... that was pretty much it. The game took like two seconds to sync the save data with the save I had on the PC version, something it did completely automatically, and that was pretty much it, I was now playing the console version of Forza Horizon 4 via the cloud with all of my cars and progression intact. If I wanted to, I could even in just a minute or two open the phone app and just keep playing from there without having to worry about saves or performance. While I'm not sure if the same cross-save thing is supported for every game, it at the very least was for every other game I tried which was honestly pretty mindblowing.
CATALOGUE:
At this point, Game Pass having a lot of games is old news. XCloud doesn't include every game available in either the Console or PC Game Pass services but it does include a lot of them, and if you've only had PC Game Pass before like me, many of those like the Xbox 360 games (which include stuff like Skate 3, Fable Trilogy or Banjo Kazooie Trilogy) can count as brand new additions to the catalogue. There's more than enough things to play and honestly, it can be quite overwhelming to choose a game since now you don't have to worry about downloading them or filesizes or compatibility or anything, but once you're after that hurdle it's a smooth sailing.
ALTERNATIVES:
The only other competition in South America at the moment is Geforce Now, which unfortunately hasn't allowed any new subscribers since launch pretty much, and for free users you're looking at hours of queuing to play just 30 minutes of the game you selected. I did manage to get in a few times though, and was really surprised at how good the streaming quality and latency is (to the point where it just straight up looked and felt native - artifacts didn't show up even when purposefully looking for them), but it's just too cumbersome and unrealiable for me. You need to log in to Steam, Epic or whatever at the start of every session to prove that you own the games, something that is incredibly annoying when on a phone or TV, you have a random lottery of PCs so what kind of performance you get depends completely on luck and you have certain quirks like EA games not really being playable at all despite them advertising so or games just randomly disappearing for days for "maintenance" with no warning whatsoever. Oh, and sometimes you might enter a game and find out their PC needs to update it which is pretty funny on a cloud service.
CONCLUSION:
I really, really like XCloud. We're still pretty clearly in the dawn of Cloud Gaming so it's hard to predict how the service will evolve, but if they just increase the quality of the stream, it might honestly be a legit preferable alternative to local hardware under the right conditions; and hell, even now, it was a pretty much flawless experience on my TV with a cheap laptop connected to it to enter the XCloud site, which is fully navigable with a controller so you don't need to worry about keeping a keyboard near or anything. Right now a PS5 or Series X cost more than 7 years of Game Pass Ultimate in my country (a service that if I were to grab an Xbox I'd sub to anyways), so it's hard for me to deny that it's just more enticing to just sub and play whatever next-gen games arrive to Game Pass than bother with ridiculously priced hardware, even if the quality is obviously not going to be the same, at least for the time being.
QUALITY:
The main thing about all gaming streaming services will always be image quality and latency. In my experience with XCloud, you could describe it as "good enough" - the latency is slightly noticeable, and the image quality is also not as good as native, but they are at least on a level where you can enjoy the game without it being annoying. It also depends heavily on what device you're playing on how noticeable it is, since for example on my PC it's often pretty clear that you're just watching a video, but on my phone or on a TV it masks all the compression artifacts really well. I've tried a variety of games on it and personally, I didn't have any trouble enjoying any of them including shooters, racing games or fast-paced platformers like Celeste. While the IQ and latency could improve as I've already said, the games themselves all had great performance and really quick loading times since iirc the servers are now being powered by Series-equivalent hardware.
EASE OF USE:
The main thing XCloud has over services like Stadia or Geforce Now, is its ease of use since by just subbing to Game Pass Ultimate, you gain access to all the cloud games that are available on the service, which at the time of writing this is a bit more than 300 games. If there's one thing Microsoft deserves props for though, is just how seamless the whole proccess is. You just open the mobile or PC apps, or even just the XCloud site in your preferred web browser, log into your account, connect a controller (including a DS4! didn't expect it to work without tweaks) if you need it and... that's it, you don't have to worry about network tests, adjusting settings, managing savefiles, updating or downloading games, etc. It's about as close to a "it just works" experience as you can get.
To give you an example, my most played Game Pass game is probably Forza Horizon 4, which I used to play the PC version of. However, since the preload for Horizon 5 was just enabled the other day and it's pretty huge in terms of gigabytes, I had to make room for it and there was no more obvious candidate for deletion than the game it will be replacing in my gaming time. As it's quite natural, once the release date of FH5 loomed closer, I felt an itch to play another Forza Horizon game again but I really didn't want to have 250GB on my PC dedicated to Forza Horizon games, but all I had to do to keep playing was click on the "Cloud Gaming" tab instead of the usual one, select Forza Horizon 4 and... that was pretty much it. The game took like two seconds to sync the save data with the save I had on the PC version, something it did completely automatically, and that was pretty much it, I was now playing the console version of Forza Horizon 4 via the cloud with all of my cars and progression intact. If I wanted to, I could even in just a minute or two open the phone app and just keep playing from there without having to worry about saves or performance. While I'm not sure if the same cross-save thing is supported for every game, it at the very least was for every other game I tried which was honestly pretty mindblowing.
CATALOGUE:
At this point, Game Pass having a lot of games is old news. XCloud doesn't include every game available in either the Console or PC Game Pass services but it does include a lot of them, and if you've only had PC Game Pass before like me, many of those like the Xbox 360 games (which include stuff like Skate 3, Fable Trilogy or Banjo Kazooie Trilogy) can count as brand new additions to the catalogue. There's more than enough things to play and honestly, it can be quite overwhelming to choose a game since now you don't have to worry about downloading them or filesizes or compatibility or anything, but once you're after that hurdle it's a smooth sailing.
ALTERNATIVES:
The only other competition in South America at the moment is Geforce Now, which unfortunately hasn't allowed any new subscribers since launch pretty much, and for free users you're looking at hours of queuing to play just 30 minutes of the game you selected. I did manage to get in a few times though, and was really surprised at how good the streaming quality and latency is (to the point where it just straight up looked and felt native - artifacts didn't show up even when purposefully looking for them), but it's just too cumbersome and unrealiable for me. You need to log in to Steam, Epic or whatever at the start of every session to prove that you own the games, something that is incredibly annoying when on a phone or TV, you have a random lottery of PCs so what kind of performance you get depends completely on luck and you have certain quirks like EA games not really being playable at all despite them advertising so or games just randomly disappearing for days for "maintenance" with no warning whatsoever. Oh, and sometimes you might enter a game and find out their PC needs to update it which is pretty funny on a cloud service.
CONCLUSION:
I really, really like XCloud. We're still pretty clearly in the dawn of Cloud Gaming so it's hard to predict how the service will evolve, but if they just increase the quality of the stream, it might honestly be a legit preferable alternative to local hardware under the right conditions; and hell, even now, it was a pretty much flawless experience on my TV with a cheap laptop connected to it to enter the XCloud site, which is fully navigable with a controller so you don't need to worry about keeping a keyboard near or anything. Right now a PS5 or Series X cost more than 7 years of Game Pass Ultimate in my country (a service that if I were to grab an Xbox I'd sub to anyways), so it's hard for me to deny that it's just more enticing to just sub and play whatever next-gen games arrive to Game Pass than bother with ridiculously priced hardware, even if the quality is obviously not going to be the same, at least for the time being.