E-Force Frame - Turn your USP into an automatic pistol (think Glock)
PIPE Front - Add some accuracy I guess...
Available Upgrades Do To Full Size Internals
Star Wars Blaster Pistol Looks
Tricky (at first) Reload
Nine Round Feeder
Exposed cup seal
There are a lot of available upgrades for the USP truley making it a tinkerers pistol. Since the USP uses full sized Pirahna internals, you can upgrade the bolt, gripframe. Also, there is threading on the USP's barrel that allows you to attatch PIPE fronts. Not sure why you'd want to do this, but I guess some accuracy could be gained. Most pistols you can't do much too, the USP offers you the chance to personalize it a bit.
The USP is pretty damn accurate for its size. You're not going to be longballing with this thing, but where's the fun in that anyways. As long as you're in a medium range, you should be able to hit your target. This is a good thin as the feed only holds ten shots.
This thing looks like a Blaster Pistol from Star Wars. If you ask me, that's pretty sweet. Sure, the RoboCop look of some of the Ariakon pistols is cool, but the USP takes it in my opinion.
Another major plus to the USP is its price. You can find them brand new for around $80 which is $20 than most pistols (Tib 8 excluded). You save some cash that you can use for a holster or upgrades to the pistol. It's (in my opinion) better than most pistols out there and being cheaper is a huge plus.
Now onto the bad:
This thing can be a pain in the ass to reload. It takes a little while to get the reloading down. I've found the best way to do it is to put your finger in the crook between the feeder and the marker and fill the feeder before getting a paintball in the breach. That's the easiest way to reload the marker that I've found and without some practice, it can be really difficult on the field.
My one real pet peeve with this marker is that it only holds nine rounds in the feeder. I would prefer ten as you use a ten round tube to reload it, and it's much safer to have a paintball in the breech while reloading in case someone tries to bunker you. Not so with the USP...
The biggest drawback of the USP is its exposed cup seal. The 12gram dropout is nice, but it puts your cup seal out in the open just asking to get dirty and ruined. It's not easy to get to, to replace either since you have to dissasemble the valve. Just be sure to store the USP with a big barrel condom on it to cover up the twelve gram area to keep dirt out. Don't store it with a twelve gram in the pistol as it can stick to the cup seal and then tear off a bit of it when removed ruining it.
Overall, the USP is good pistol at a great price. It has some drawbacks, but also has a lot of pluses to it that other pistols are lacking. And at its price, it's hard to beat. I give it a very solid 9/10.