The USP-9 is my department's issue pistol for uniformed carry. Butt-ugly, but reliable, durable and reasonably accurate.
However, when I carry a DA/SA semi-auto (not the usual 1911) off-duty ... it's a SIG (228 or 226). Likewise, just about every guy I work with carries
anything but an H&K off-duty ...
I might give the edge in durability (for long-term hard use) to the H&K, but as far as accuracy, the nod goes to the SIG. Reliability is a wash ...
I think you can do more with the SIG's trigger (different options available to change the pull according to personal preference), which is better out of the box than the H&K's anyway ...
And I challenge anyone to tell me the clunky USP has demonstratably superior ergonomics to the SIG P-series (in my experience, more folks will say the SIGs feel much better in the hand) or can be concealed nearly as well.
As others have noted, even though the OP did
not ask, H&K does produce some other fine pistols; the P2000 comes to mind, and the P30 seems an enticing little package. However, because of the allure of traditional steel and wood, the SIG wins on class points alone; you can get nice duo-tone packages and dress 'em up with nifty wood stocks ... rather than put up with a boxy black critter with cheese-grater checkering on the plastic frame ...
And hey, how 'bout the folks that say things such as
Get yourself a P2000 or P30. Hate to say it, but these are better guns than P226.
but can't be troubled to type out even a sentence or two in support of their opinions?