Well, I could go one and one about the good things, but let me mention some negatives that I don't see the reviewers mentioning:
1> The Mini-Map is too small and contains too much information. On my PC, when I'm sitting 24" away, it would be fine. But across the room on a TV, I can't see the little dots for [censored]. And the icons are damn near indeciperhable even when you can see them. Pay-n'-Sprays are the worst. Without the fold-out map to direct me, I'd never be able to see them on the mini-map.
2> The cities might just be too big. And not only that but they're extremely 'cluttered'. Streets for the sake of streets in all sorts of unusual directions. A city planner would be horrified. It doesn't take too long to learn your way around Liberty or Vice City but I can't see myself ever learning my way around San Andreas. Thank God there's a decent map available when you press the Start button.
3> Feeding CJ can get very tedious. In another game, it wouldn't be so bad. But in GTA it just kinda breaks the mood when you gotta stop to go find some food.
4> The Wardrobe system, particularly buying clothes, takes forever. There's some 10 items of clothing you can change on your character, and in some cases up to 20 options for each. Each time you pick something to 'try on', you walk into a closet, wait 10 seconds, then walk out, and decide wheter you want to buy it or not. Picking a shirt can take 5 minutes just to see the all the options available. Changing an entire outfit can take 15 minutes.
Well, those are my big ones so far. I still stand by the game being easily worth the $50, I just wanted to point out some negatives as the reviewers seem to be focusing on the positives as is usually the case for such a big game.