Let's See... Everything. It looks great and performs well. I have not had any trouble with it. It out performed my friends guns. The grip is awesome and feels great. I have a different barrels but the zero-gravity barrel was better than any stock.
not much besides the fact that the trigger shoe fell off but that was easily remided.
IT's a good gun for the price. It doesn't have many upgrades but who ever said it needed them was wrong. I love this gun. A few self mods and it is shweet!!!!!!! Get this gun over the tippman or the spyder. I give it a TEN!