I don't have any experience with PC sticks, but do have some experience with single-board Windows 10 machines. I've used both the Latte Panda and a Zotac picos. In my experience using MAME on them, they can run the 80s stuff fine, decent amount from the 90s. I'd be shocked if they could properly handle the PS1 (but I never tried).
It is getting better all the time though. And there are more and more competitors in that area.
I researched a few pc sticks from intel and others when I was doing my miniature builds. What ended up holding me back was the number of USB ports and the power (electrical) they provided. I wanted to use the pc itself to power the speaker, screen, and controls. I wouldn't have room to add a USB hub or separate power supply. Just something to think about for whatever you're building.