The FM music certainly isn't bad mainly because the composition itself is very good, however the sound QUALITY isn't as good as the Genesis can do. You hear the FM music slow down whenever the game slows down. What's weird is that Tiido Primagi did the sound engine, but this one must be made to fit in a much smaller space or maybe the composer didn't use a good sound set with it, because Tiido's sound engine is usually really, really good.
Anyway, here is an example which compares the FM and CD title screen music:
Whoever made this video must have a model 2 Genesis as it sounds pretty scratchy, especially in the high frequencies.