My feelings are that they are extremely well made polymer guns. Their fiberglass reinforced polymer is the strongest used in handguns today and I doubt you will find a more accurate off the shelf gun. You will pay significantly more for an HK compared to other polymer guns not to mention the very high price of their magazines, but you know you are holding a quality firearm when you pick up an HK. Having said that, the negative comments against HK generally have to do with the fact that they cater to the wants and needs of the military and police.....not the consumer. Their customer service isn't great as we are not their bread and butter. On the otherhand, their guns are so well made that you probably won't need them all that much and the guns are worth the money IMHO.
With respect to the USP, it's a great duty gun but terrible for concealed carry...way too large and bulky. They did come out with a USP Compact that is much better for CCW but have since introduced the HK 45C which is the next gun I have on my list. The HK 45c is perfect for 1911 aficionados like myself as the manual of arms is nearly identical, including thumb safety (assuming you choose that variation and not a LEM trigger). Another nice feature is that you can use the thumb safety as a decocker as well, which leads HK marketing people to call it the 1911 of the 21st Century. The gun is just a work of art and feels great in the hand....albeit not cheap. For 9mm or .40, the P2000SK is very nice and compact and the P30 for 9mm only is nice, but not as concealable as the previous two I mentioned.
Great guns if you don't mind spending the money.