I love the HK45 look and feel, Its accurate and runs great, but its a bit big to carry for me. I carry P2000 or VP9sk. But I think the hk45 is huge improvement over the USP with pic rail, grip panels, rounded edges, but still not a carry gun to me. Its my HD gun with light on it, and my wife and kids shoot it well enough for home duties.
45 has lost popularity across the board along with 40, but its just the ebb and flow and will probably be popular again....
I agree ergos trump weight/capacity.
Those 2 rounds could save your life.