I played this game for a bit last year, until some typical Rockstar incompetence pissed me off. In addition to my other rants, the game was hanging when manually loading a save. I tracked this down to being online, and possibly also related to having some of the free GTA-Online DLC present. Going offline allows save-file loading from within the game again. (This is now made easy by rejecting a GTAO-related update to the game, which kicks me off of XBL.) And a screen was asking me to sign into a profile when I was already signed in; but this screen is frozen--no response to any input. I tracked this one down to the code stupidly looking at the 2nd controller. Unplugging it solved the problem.
I played several other games in the interim, but finally I went back to GTA. Once I got into it, I could not let it go for weeks. While some obtuse design remains, much of the hair-pulling frustration of previous iterations has finally been solved. The checkpoint system for missions is terrific. No longer do lengthy sequences need to be repeated when a mission fails. And saving progress can be done instantly from the cell phone. The only reason for saving at a safe house is to advance the world's time by 6 hours (which helps mission progress sometimes). These improvements pretty much cure rage quitting, and have kept me chasing the mission path a lot more closely than on any previous GTA.
I finished the story a couple of nights ago. All 69 missions complete, in fact. That was quite a trip. They really outdid themselves with the writing and acting. The 3-character mechanic adds a whole new dimension to the freedom of the open world. My favorite character was Trevor, until I discovered Franklin's special ability, which completely outshines the other characters'. It's funny that it took me nearly 100 hours of game time to realize just how terrific it is. I spend most of my time in GTA games whipping some vehicle or other, and this slo-mo plus enhanced response is the tits. Plus once Franklin buys LS Customs, it's too much fun modding every car he comes across, for free. Trevor still wins as my perverse alter ego, though. Michael brings up the rear by a fair margin. He's so vanilla.
Technically, the thing is a marvel for such old hardware. Looks terrific, with rich detail, and the frame rate holds up most of the time (though it does get chuggy on occasion). Except for the problems I already complained about, the game did not hang on me once, in well over 100 hours of play time. For an open-world game, that perfect record is unmatched in my experience. I will guess that installing the whole game (half to the HDD, half to a memory stick) aided that stability.
I love the variety of vehicles and the many truly different things to do. Every day seemed to bring something new. It kept the experience from getting stale. I'm still trying to tackle some unofficial challenges, like parachuting into Fort Zancudo, and making off with a fighter jet.
The only other complaint I can come up with is the limited and dodgy saving of vehicles. Rockstar should learn a few things from Saints Row IV, where anything you ever used can be recalled later from a list. If that's too much, then at least take the time to fix the disappearing stuff, and give us much, much more garage space. This is LA. I want Jay Leno's garage.