I liked SR3 and was impressed with this game graphics wise and gameplay wise compared to the previous games in the series. There is a lot more involvement with this too and I think the character styles and choices is better than SR2 and the game is much more fun with the cool features they added. Although, the storyline in this game started off great and was good til the end but I finished it very quick and it was easy. I can't do a second play-through though unlike GTA games.
But with that being said and me saying some SR3 features are better than SR2's, I'd still say SR2 was better. Like other game series, there is only ever one or two good games and remakes can't beat it.
For example; Call of Duty 4 was much better than the CoD's after it.