From a former Stadia user; latency was never an issue or noticeable with a 4K stream. And I've played quite a bit of fast paced shooters in the platform.

The experience is extremely dependent on location, bandwidth, local setup and availability of close services (in my case, the closest DC was <15ms away according to Stadia telemetry).

You can't play an fps with them but they are fine for turn based strategy and similar games. I did some beta testing for google stadia with assassins creed oddyssey when it was still being conceived, and while it was mostly playable (single player game though, I would not consider it competitively playable against other humans), even with my wired 1g fiber connection the service would have these huge drops down to almost 144p quality along with framerate issues.

Not the OP, but i know for something like PlayStation Now, it was acceptable for most games. It was a pleasure to just decide to play a game and well yeah, I was playing the game. The latency wasn't a concern.

I couldn't see myself playing an FPS on it, but then I prefer kb/m anyways. But for the games I play on console? It was fine.

There can still be issues, of course, but the latency overall wasn't a deterrent.

You can try it for yourself with Nvidia’s GeForce Now free tier. Just connect with Ethernet if possible.

My experience is that it’s definitely playable and beats a low power laptop with an underpowered video card. Latency in the 40ms range, and barely perceptible.

I have 100Mb/s internet and I cannot notice it on Ethernet on my M1 MacBook Air or on Wi-Fi on my iPhone or iPad. Wi-Fi on the M1 Air is garbage so it's very noticable there.