I love mine. Recoil feels different due to the rotary barrel, and I prefer it.
I was a 1911 guy and never could drink the Glock Kool-Aid. I bought two, and tried hard to feel the love. Had to give up. Didn't dig the grip or the mushy trigger.
The GP K100 feels great in my hand. The double action pull is long, but smooth. Not nearly the equal of the SP01 Shadow's DA pull, but good. The single action pull is very nice and the reset is fantastic.
Don't get creative tearing apart the lower, as it's a bit funky going back together. The ball detents that give the safetys thier resistance make reassembly interesting. The spring that tensions the recoil spring guide is also a bit hard to get right. The lower is assembled using stainless steel pins instead of the more common mild steel roll pins.