I'm using Hyperspin, I picked it after spending a couple years with GameEx. I picked GameEx at first because of the easy setup, where Hyperspin is a bit of a hassle to get together or so it seems at first if you start reading all the documentation.

But once you got their base concept of XML files running pretty much everything it becomes crystal clear and Hyperspin allows much more customization to get a pixel perfect display or close by for every game on any emulator. Once setup it's totally stable and doesn't require any kind of maintenance, so I would say worth the sweat.

That being said I have a package with Hyperspin preset for 15k screens, a bunch of emulators and bunch of games that I'm happy to share with whomever needs it.

mGalaxy looks quite interesting, especially on the setup part for multiple emulators. I don't see anything in the main section (but didn't dig the documentation) regarding handling VGA support and multiple display resolutions for a CRT screen. What do you run this emulator on ? and do you know if CRT screens are supported ?