As someone all in on Game Pass, I think PSNOW has a better library than GP but what weighs it down more than anything is that sub fee. With my internet the streaming performance is pretty good but not great, but my biggest issue that prevents me from keeping it is the buy-in price. Also afaik Sony never has sales on subscription periods for it like GP does, you can tell they aren't really concerned with making it a big thing this gen considering their catalog (PS4 library that is) and general install base as is. That said it is pretty impressive wrt the catalog in general, I tried a bunch of exclusives I missed out on during PS3 gen, and it has a pretty decent lineup of fighting games too.
If Sony beefs up their cloud+streaming tech to make IQ and general perf better, plus slaps a more competitive subscription price on it then it'd be attracting a lot more users. Obviously bandwidth speeds are scattershot in general in certain parts of US so that's another issue. I'm fortunate that in my area Comcast has only increased speeds over the years without making it cost much more so I'm set, but for Joe Midwest that has fuck all for options due to lack of infrastructure and isp availability there's another reason this sort of thing isn't taking off. Also something is gonna need to give between Microsoft, Sony, or whoever is hosting these streaming services and ISPs with data caps. It's nutty how fast you can reach that 1tb Comcast limit with Game Pass.
It's gonna be interesting to see how fast it gets there with a higher quality streaming tech like xCloud that I'd assume uses more bandwidth. Somebody's gonna end up paying eventually to make that cap go away and I'm guessing it's sooner gonna be someone like MS paying off Comcast or whoever so their streaming service can reach people unfettered.