By far the best GTA game so far, more enjoyable than San Andreas in general
In short it is better for it.
The game follows Tony Cipriani on his way to becoming a made man and beyond in the mafia. This allows for satire on The Godfather and Goodfellas as GTA 3 did, but here the humor is more obvious and quite frankly funnier than that game.
The maps are of a descent size and suit portable gameplay more than the sprawling monsters that were in San Andreas (SA). In fact due to their more compact size the are more easily remembered than SA's and therefore easier to navigate, this makes it easier to complete the missions and also means the travelling from A to B doesn't become a chore like it did in SA.
The radio stations here are fantastic with Liberty City Free Radio as the usual talk station with the embryo of what became the Chatterbox station in GTA3 in there, also returning are Flashback, Head, Lips 106 and K-jah.
The game will last you forever as the free roaming structure returns and the plentiful sub-missions and multiplayer to keep you occupied long after the main game is over.