PS3 and PC owner here, ended up buying GTA on the console. Very nice, very real, very dull.
Once I completed GTA SA I was able to go back and spend hours just dicking around and then turn off without having to save, hours just playing for fun with no hint of trying to achieve anything. The problem with GTA 4 is it decided to lose the crazy shit. The stuff like jumping off that huge god damn mountain (mount chilliad) on a bmx or a quad bike and surviving, stealing a military jet and going on a rampage, jumping in a monster truck and going on a crushtacular rampage. It was the madness that made GTA SA and the games before it so fun.
The maps were interesting with each local having something that made the maps memorable and interesting. Just for example look at the airport in LC Mark I and the airport in LC Mark II. The one in Mark II is much larger so their should be far more going on far more to get up to but their isn't. Mark I actually had aircraft landing and taking off, Mark II just has an aircraft that goes round and round forever, nothing coming or going. Mark I had the Dodo, you could spend hours trying to get that thing to fly, Mark II has nowt. I could navigate from any point in SA to any point in SA and the same went for VC (Vice City) and the first LC (Liberty City) and it was down to the interesting landmarks in the city that made them worth remembering.
GTA4 whilst enjoyable in it's own way and very nice to look at is frankly dull. The city is just another city; endless streets that all look the same. Why do you think they gave you a sat nav to get about with, because the map is so unforgettable you won't bother to learn it. The funny thing is whilst their is more life in the streets of GTA IV there is much much less of note actually going on.
I should be annoyed that I won't get the DLC but frankly I am not. Liberty City Mark II is not a city I want to go back too. Unless the DLC adds content which brings back the madness then I can't say I am that bothered about not getting it. What could bother me though is if Rockstar are busy diverting resource from the next GTA game to scoop in cash with daft DLC content but I gotta a feeling that GTA 4 is a landmark in the GTA series. The death of the sillyness that made GTA so fun. I am worried that the next GTA will not magically reintroduce this sillyness and for the first time in almost a decade I am seriously considering NOT buying the next GTA game.