Making my fifth cabinet currently, and this one will be a gift for a non-technical friend.
All of my previous cabinets have suffered some sort of hardware failure in their life. Getting in there and troubleshooting a whole PC that is intermittently failing is a pain in the butt. Dealing with trying to get adequate cooling and fans working, mounting video cards properly if they're not onboard, and other dramas has been annoying.
I'm going with a Raspberry Pi for this current project, as it's going to reduce a lot of problems. All of my previous cabinets ran Linux (I'm a Linux sysadmin by trade, so there's zero learning curve for me). The cabinet itself will only need to run 80s games (the recipient is a guy in his 40s who has no care for 1990 and newer games), and the ~5 games he really cares about are all supported by MAME4ALL.
I'm liking the idea of something that will power up easily when the cabinet comes on, but small and power friendly, and have no real need for massive ventilation requirements to work. Mounting it will be easy enough. I can take an image of the SD card with the games and config, and replace the RPi easily if it fails.
For this particular cabinet, it's a win. I wouldn't put it in a cabinet where I wanted to run more modern games (CPS1/CPS2 fighters are my thing, so I'd avoid RPi for them).