A ripoff of what? GTA?
I guess you could argue that, but really people claim every sandbox game ever is a ripoff of GTA now. Hell, I remember people saying the Spiderman games were just GTA with Spiderman. Lol. My question is, so what if it was? Does that make it any less/better of a game?
Anyways, SR does some things better then its counterparts. For one thing, customization. You can fairly easy create a character that looks just like you. Or whoever. And now being able to customize every color (which you couldn't in the first) I was able to make the same exact outfit I was wearing the other day, something you can't do in GTA, or Crackdown, etc. It's also fun. A lot of the tongue in cheek humor, that used to be in the GTA games, but was removed in IV is there, such as activities like Septic Avenger or Crowd Control. Overall, even though I loved GTAIV, I personally think SR is just more fun.
Also, one complaint I saw about SR was that it was too short, or not as long. I completed the game yesterday, and was done at 25 hours. And the only activities I really did were ones that were necessary to continue the story so I didn't just waste a lot of time doing nothing. So it's definitely longer then I remember seeing some people complain about.