It's ok if you don't mind the graphics. I mean once you play games that are visually appealling like Dead Space, ToV, Gears, SF IV, you become spoiled. It looks better than AC4, but t still looks dated. In fact, when your waiting for the game to load in between mission starts or arena battles, they show models of the robots that look very generic and plain looking. It's like they have no texture or anything to them. But the customization is on point, the voices sound ok this time around, and the music is your typical AC music (techno sounding shit.)
Rent it first, and if you can see yourself plying it cop it. I copped mine for $19.99 new and had been looking for it for some time, but peep it out.
Edit: I forgot this, and this is very important. The controls have been changed a bit and they are changed for the better.