Yeah, it's a good emulator. It doesn't have as many problems as I originally said.

I think they should compact romsets into a single file (i.e., .arc for arcade, like .nes, .pce, .smc, etc.), if that's possible, so that you can associate the file type with the program and just double-click it to make it to run, and they should maybe provide compatibility lists for romsets so that it's easier for ROM sites to know which versions to host. It seems like there's some confusion here.