I purchased it immediately because I don't have a console and didn't feel like forking out $500 for one. At this point, you can run it on your own Chromecast Ultra (assuming you have one) so the price boils down to the controller if you wanna play on your TV or you can play in your browser on your PC. There is a monthly subscription fee (a couple of bucks higher than the comparison) and the games are often a few bucks more expensive as well.
In terms of performance, I have a 400 Mbps connection and I have yet to experience an iota of lag. It's actually quite insane how it works: you do something on your controller, it send a signal over your home WiFi to Google's servers, the action is registered on their server, the image is updated and the image is sent to your Chromecast, with ZERO lag.
I imagine if you have a shoddy connection and you're attempting to run this over wifi, you may experience issues. But go into this with the proper setup, and you will not be disappointed. A lot of people compare about Google's promises during the sales pitch (namely 4k 60 fps which is missing from most games), but the end result is a very impressive gaming experience.
I'm definitely sold, and after Borderlands 3, Cyberpunk is my next target.