The HK USP .45 (I own one) is a good gun... but heck, it's not worth anywhere near $1000.
Mine has broken firing pins twice*. The Chamber was bored eliptically, and there is a lot of muzzle flip for a gun of its weight. Accuracy is good if you're shooting SA, particularly with the $100 drop in match trigger.
But, you're effectively limited to 10 rounds, and the creepy, "sproingy" double action pull is still an abomination--way worse than Sig.
Biggest problem with the gun is long, sloppy trigger reset. This leads to the "click no bang" phenomenon many of us have experienced with the USP in rapid fire. After firing you release the trigger until you hear the click and feel it reset. Pull again and--guess what--nothing happens. Makes for a very frustrating rapid fire sequence.
It is a flawed gun with a very nicely machined and fitted slide and barrel. The biggest plus is that it Never jams.
But I won't use it for defense any more because of the firing pin issue. Without a firing pin, your USP is just a brick.
*The second time HK replaced the whole gun because the front half of the firing pin, during recoil, wedged between the frame and slide on the rear, taking a chunk out of the polymer. The back half of the firing pin ejected out the back of the gun and hit me in the face. Lovely.