I found the story in Mafia 2 to be rather interesting. I especially loved a mission that well... If you haven't played the mission I won't spoil it, but suffice it to say. If you played the first Mafia game, you'll recognize one of the characters. I also found enjoyment in the ending as well, it was a rather nice twist to it and I'm curious to know how it all turns out if there's a third Mafia game.
Gameplay wise though, it was kinda easy. Once you find the gun you handle the best it kinda becomes TOO easy to get repeated head shots. I swear, during the last level I actually got a head shot on nearly every enemy up till the climax fight. Even with the easy gameplay, it didn't distract from the fun of the experience itself. The cars felt slow but that fit with the timeperiod and each car FELT unique while driving it. Not to mention how some just looked freaking awesome.
All in all, Mafia 2 was a great game to play, fun and interesting.