Quick assembly (but see the weaknesses...)
No more CO2.
No more dry ice.
Pre assembled components can have a "square peg, round hole" problem.
I had but one difficulty with this: The power tube/valve assembly wasn't lined up right. As a result, it took me a clamp and some serious elbow grease to get it in place, and I almost stripped the screws that hoild it in place. Oiling this sucker's difficult because of that. Also, the window cover (goes on the side of the gun) is a pain. Screw it in too hard, and the grommets bend and pop out through the window, or the cover cracks. Too loosely, and the bolt jams against the grommets. If they'd either let the buyer assemble the parts or take a bit more time to make sure everything lines up right, this would be perfect. Just be careful with the grommets, and if it's necessary, use a bit of force with this thing. (Clamps help.) I suppose you can't expect every single kit to fit every single time, but hey - that's how it goes.
Definitely worth your money, search around for a good deal. Just don't get frustrated with the installation.