Latency is pretty bad (GFN by comparison works fine for me). Samurai Shodown, a brawler game, is mostly unplayable.

The overall quality is very beta (black screen in Stadia unless you disable hardware acceleration, which I have to do every time, Stadia can't easily handle multiple Google accounts, I have to change accounts every single time).

Probably worst thing is very Google-like support. Super long queues for "Customer Care", phonelines are closed at 10:30 AM because they're "Out of hours".