I could see how some competition shooters wouldn't like the standard HK trigger. It's pretty flexy. But other than that I'd say cost. My USPc .40 cost me a little over $900 OTD, and I could've gotten a G23 for what, around $600 OTD? That leaves a whole lot of room for upgrades and customization.
But then again I've never shot competitively, so I really don't know.
But then again I've never shot competitively, so I really don't know.