Apart from the occasional hiccup, quality is fine. I am sure that if you did a side by side comparison it would be obvious, but I can honestly say I don't notice 99% of the time. Once you are in a game and playing, it is totally fine.

In the same way that when you are watching something on netflix or amazon or disney etc, when you are really into the movie or show no one ever stops watching and thinks "gee I just cannot watch this - it is not Blu-ray quality!".

Just like with netflix et al, game streaming is amazing - pull out a thin and light laptop, browse through a large catalog of games and just pick something and play immediately. The "legacy" approach is physically go to the gaming PC or laptop (because you need the hardware), wait for it to boot, wait for the inevitable updates to download for Windows and Steam and Graphics drivers, browse through your game catalog, wait to download the 20-30gb install, wait for the VC redistributable to install, then wait the game itself installs etc. It sucks - you waste so much time. With a Chromebook and geforce now (rest in peace stadia) I can literally go from a closed-laptop to in-game in about one minute. This is the future.