It's my favorite of the GTA games, and I think there's a number of things it still does better than any others in the series, such as properties, turf wars, the sheer scale of things, the jetpack, the harrier, the minigames (like multiple casino games), the radio channels, and the overall story / mission structure. But it has been quite a long time since I've played it and I don't know how well it all holds up. If you like the last-gen GTA games (III and Vice City), it's worth it, as it's the best.