I have and shoot both in DA/SA, but I prefer the USP45 over the HK45 because I like the blocky grip with the edges and the more aggressive texture. Better purchase, better feel, better accuracy.
With the USP45, I've punched 2-3 inch groupings 15-18 yards out, two-hand shooting, slow relaxed fire.
With the HK45, it's about 3-4 inch groupings, same distance, same style shooting. But the gun, despite the ergo batman grip with the light sand paper texture, tended to slip in my hand shot-to-shot at time. Found that to be annoying.