Streets of Rage II & X-men are worth $20 combined (if they're complete), $15 or so if the manuals are missing. So yeah, it's a good deal. Unfortunately, that model Genesis has the poorest sound quality because Sega changed some sound chips from the first models produced. If you've never owned an earlier Genesis you would have nothing to compare it to anyway, so the difference isn't noticeable to most people.
Enjoy SOR II - it's one of the best Genesis games ever made.