I updated to the latest firmware couple of weeks ago and then went ahead and hacked it to run batocera. I would say it runs up to PSX at full speed, most mame/arcade runs well (only ones that didn’t run great were things like vf1, tekken arcade roms etc and in those cases the 32x vf1 port is a good replacement and the psx tekken games run really well)
There is a Spanish image of roms that is popular, but honestly I’ve spent the last week populating with my own and matching up vids and screenshots
PSP some games are playable, others aren’t
N64 most are playable at full speed but ymmv
There’s a mixture of retro arch based cores and then some standalone emulator also, but really it could do with bringing up to date with a fresher batocera image. Been looking into how to compile that but it’s a steep learning curve and the original dev that did this has moved onto other projects and there hasn’t really been any work on updates since end of 2022