The gameplay looks absolutely amazing. I was wondering how they would outdo GTAIV, but it seems like they're on their way to doing so.
I especially like the way controlling 3 characters seems to work. If I understood correctly, you'll be able to switch at any time and see what the other character(s) are up to. That makes it seem like they're putting more of a focus on individual characters having more developed lives.
I can't wait to play it, seems like a blast