I've been using my Moto Z Play in place of my S9+ for the last few days and I still enjoy it quite a lot, maybe even enough to sell my S9+.
It's still fairly smooth (not as smooth or fast as the S9 for sure, but not bad at all), it's nice and light, and the battery is still fantastic.
While I do like the big, bright, tall screen, the nice camera, the waterproofing, and the samsung pay on my S9+, the weight and the battery life were starting to bug me. I thought I'd get used to the weight after a few weeks, but it's been a few months and it still isn't super comfortable to hold for too long one-handed. And I haven't run out of battery with it yet, but I get down to 30% or less most days, and if I'm using GPS much I definitely have to plug it in or risk getting down to single digits.
As much as I like all the nice features, I usually have to go out of my way to use them. I barely ever take pictures (my fiance does all that, haha), have to make myself remember to pay with Samsung Pay, and while I thought I'd LOVE the HDR screen, there's still not much HDR content for mobile devices (once 4K screens are common hopefully VUDU and other movie companies will let you do HDR for out digital movies). Plus the sooner I sell my S9+ the better the price will be, it's already lower than I'd like.
Wish I'd realized all this before my return window expired, but I had the itch for a new device and I have enjoyed it while I've had it. Think I might hold onto my Z Play as a permanent backup phone and maybe try out an iPhone this year (if the rumored X2 Plus isn't too ridiculously expensive and has a good battery life).