While I prefer Gens most often, the fact that I have to use other sega emulators for Langrisser 2 (with the english patch) because it 'crashes' with Gens, kind of pisses me off at times.
I can't really vote because of that little fact. I mean if there's other fan translated games that Gens can't play on exactly, but Kega might, then my favor would sway for Kega.