Well...I guess that I'll have to be the voice of the opposition. My team uses the USP tac for our primary secondary (M4 on point), and we carry the P2kSK for a backup - backup. Damn accurate, easy to hide, thinner and lighter than the USPC. Think about purpose here...how far are you going to have to shoot it (kills velocity issue), think about where and how you are going to carry it...I am a soild 15 stone, and I can't make a USPC go away under a shirt (no issue with the SK).
Lastly...quit being a bunch of ...and put one in the pipe and go. I love SA, but when you need it for real (have) that first round comes off easy, and DA is a must.
Everybody has an opinion here, but look to those who own the equipment, know how to use it, understand the issues on both sides, and who are actively trusting their live to it.
IO1 out.