I'd say this is graphically slightly better than every other streaming service I've tried, including PS Now, Shadow and Stadia. Lag is always going to be a problem with certain games, no matter what anyone says, but the selection here doesn't especially suffer with it. The games play well and look really nice on my tablet and phone. I do also really like just clicking on a game I don't have installed and getting straight into it, it's a cool way of trying stuff out.
My issue is the audio, really. The microskips are just distracting enough to pull me out whenever they happen, which is every five seconds and almost constantly with FH4. I might use it if I left my Switch at home on all trip or something but there's virtually no chance of that happening, anyway.
For context, I'm on BT Infinity 2, can stream 4K UHD movies without a hitch/artifacting, etc.
SoR4 - Good response and graphics, audio not too bad.
Ori - Best on every count.
FH4 - Looks great, response is sluggish as expected, audio is poor.
Halo 5 - Artifacting, laggy, audio not so bad.
Sea of Thieves - Probably all right, couple of beers in a hotel room, audio a bit bit crackly but plays well.