GTA IV has the top score this generation so far, according to most. I think Gamefaqs READERS did that.
But GTA IV sucked, hard for me. I can't believe they removed so many features from the previous ones that separated it from the clones and wannabes. The mission didn't have the creativity I expect out of the series, I mean most mission/quest based games have you doing variants of the same thing but man GTA it so obvious you are doing the same thing.
The storyline just feels annoying, it attempts to be way too gritty.
I think many reviewers got caught up in the atmosphere the game creates off the bat, and I think if you asked most now they wouldn't say it's a 10/10 game.