They were better at different kinds of music, Genesis in general having harsher sounds that work better for more aggressive music, so when it came to more chill tunes, the Genesis fell flat on its face. Just compare these two:Yea, sorry... you're talkin to a Sega Genesis guy, I love the Yamaha YM2612 sound chip more than whatever MIDI shit the SNES uses.
Of course, you've got other factors like just flat-out how talented and familiar the musicians are with the sound chip of each system. It's kind of a nightmare to work with.
Post some songs where the Genesis version sounded better, because, uh... I don't know of any