I would give this game 5 stars if it wasn't having so many issue with connecting. But from what I've researched it's because the game exceeded expectations and sold more copies than anticipated. When you can play, the game is absolutely amazing.
I'm looking forward to them adding more content. I've read the 1 star reviews and it seems like those people either didn't give the game a chance, couldn't connect and gave up or are just bad at video games. I don't think it's fair to review a game if you haven't fully played it. With that said I'm level 21 and have played quite a bit. It is a difficult game but is a lot of fun with friends or even matchmaking (when it works.) I don't think this game is going to be great for someone playing by themselves. But all around I'd say one the of the best multiplayer games to come out in a long time.