Psg owns FM, period. Fm has some good tunes, but psg has far more good tunes. The best of fm doesn't compare to the very best of psg IMO. Not even close. There is WAY too much fm garbage music out there. For every Streets of Rage there are at least 300 crappy "tinny" and "abrasive" and overall crappy fm tunes. For however much psg owns fm, multiple the amount of ownage by at least 1,000,000,000,000, and precede ownage with words like super, mega, and hyper, and you have an idea how much psg owns redbook, especially early redbook.
Redbook is decent, but the instrumentation is worse, because in 99% of the cases, they have synthy instruments that are trying too hard to sound real, but falling very flat. Mostly sounds like uninspired midis on steroids. Instrumentation aside, lots of redbook is mundane, and bland. You can tell when they got lazy. Kaze no Xanadu may not be my favorite pc engine rpg or game by far, but I have to give them a MEGA thumbs up for making 99% of the game's sound track in psg, and very well done psg at that. The kick ass music was one of the few things that was able to keep me going for 6 hours straight without pulling my hair out trying to figure out what bastard I needed to talk to that I couldn't find, or wasting 10 minutes at a time traveling from one end of an area to another to see if I actually triggered an event.
I wished they still made most games with psg music, I'd probably buy some of the crap they shit out nowadays if they did. I would totally buy rock band or guitar hero, if it was all kick ass psg music.
OBEY PSG
DESTROY REDBOOK