During the free time of Geforce Cloud (forgot the name), I tried the free tier.
It was neat but unremarkable.

Also tried the offering from Microsoft to play Halo 5 on my phone with an xbox controller.
It was a bit laggy but still doable in the campaign.

Nowadays I’m not so sure. Not even sure if my tries were so laggy due to my home infrastructure or because the datacenters were more far away increasing lag.
As per Youtube videos: Should be pretty neat if you can stomach the minimal lag