Things I liked: How about the that 6-round burst mode at 600 rounds per minute? That's the reason to buy this gun.
Things I would have changed: I bought this from Pyramyd Air before the release of the Blackbird model. The Blackbird addresses the two shortcomings of this gun: the need for more air and more rounds. (You'd be surprised how quickly you'll expend your 40-round clips and freeze your C02 cartridges with that 6-round burst mode.) The sights aren't the best, but the Blackbird offers a better rail for mounting scopes. I don't know whether I'll buy the new, improved model, though. (This gun is fun as it is.)
What others should know: This isn't the most accurate weapon, especially with the cheesy sights. But it lends itself to some fun 'spray and pray' destruction of glass bottles. (I can still recycle the broken glass as easily as whole... so why not?)