I agree with the sentiment that it's refreshing to see a simple 4:3 setup in a classic looking cab. Anyone can make a pedestal with a big ass TV on it, and make it look okay. Pulling off a machine that looks like it could be from an earlier era is where a lot of the charm is for me. Get me drunk on some nostalgia.
As for the Pi comments... I dunno... I use a Pi and have a good deal of success. If someone tried one a few years ago and didn't like it, but hasn't tried one since, they have no business writing it off so casually IMO. Earlier iterations had some shortcomings but with my Pi3b and a mild overclock, it seems to handle a lot without issue. I would take it over a Pandora's Box for its ability to be tailored to your situation. People looking for plug and play may find it lacking and wouldn't argue it away, but the Pi is useful beyond emulation and serves perfectly fine IMO as a stepping stone or stop gap on your way to a PC or original hardware.
Keep up the good work. Looks very clean. CNC is king... Only wish I had access to one.