I've been using Boosteroid for the last few weeks and am finding it to be an unexpectedly good experience, with a few major caveats:
1) Assuming you're using a Mac, the Mac version is still in beta. It's improved noticeably day to day through regular updates though, but is still a tad rough.
2) You must have good solid download/upload speed on your network, and I do NOT recommend bothering with this service on any kind of wifi. I'm playing with my MacBook Pro connected directly into a Velop mesh node via a Belkin USB-C to ethernet converter and a Cat8 cable, and I get a consistent 60 fps on Elden Ring.
3) Speaking specifically of Elden Ring, it will not give you button glyphs for any controllers other than an Xbox controller, at least not that I've been able to figure out yet. So if you're using a DS5 like I am, you have to just replace the buttons in your brain. I don't have any trouble adjusting, but I'm used to having to flip back and forth between Switch controls and PS controls.
Overall though, I'm super impressed with the service and not sorry I paid for a year. Hopefully by the time my sub is up, there will be a ton more titles available natively and I can just cancel it. The fact that you're really just buying games in other stores for the most part makes it so you're not trapped in Boosteroid forever to play your games if they get ported. It's kind of just like renting a gaming PC when you think about it.