I don't know I haven't seen enough ingame footage for either game to decide, i wasn't into the first 50 cent game on the original xbox because well...it was a 50 cent game and I don't know but a game based on a rapper just seems like it would suck but yeah, I heard 50 cent 2 would have multiplayer and thats pretty much I care about anymore.
Saints Row, if its anything liek the first one I probably wont touch it because I got GTAIV and whats the point? Saints Row online sucked in the first one due to the fact that there was hardly anybody playing online ever so I can't imagine it being any different for #2 but we'll see...