Everything. I bought mine a few weeks ago and its sweet.
The accuracy is eccellent, actually put a laser sight with a 2x scope on it, and its efficiency is awesome. It doesnt use very much paint at all, i lasted six hours with 200 rounds. its because of the acuracy too.
I like the field stripping because you just unscrew the thumb screws (which now have o rings in them so they dont slip.) and clean it. It has very solid parts but the casing might be a bit thin. An excellent marker.
Nothing i can think of. But the grip can sometimes get uncomfortable.
The price can be a bit steep but it's worth it if you're serious about pump playing.