Best game in the franchise. A good enough blend of grounded seriousness, second degree satire, and "shoot first ask questions never" attitude. Constrasted with the dark tone of GTA IV. Those games were never meant to be competitors. Too bad some people thought you couldn't enjoy both so they ended up ruining the series afterwards. Fun action game and the full coop mode was certainly a solid point of it's own.
All issues aside, this game reminiss me of HD Fallout : they can't decide between FPS shooter and RPG. You end up having ridiculous combat of NPC with weird pathfinding and what appears as lethal guns but despite headshooting someone 15 times, he won't die. Those games ought to have a light mode for people who just want to open a FPS-Openworld and the narrative, with people dying from lethal wounds instead of being an ammo scourge.