I'm a huge fan of the GAP guns. I would highly recommend the G39. If you haven't shot one, you'll fall in love instantly. The .45 GAP is an amazing round. Same size bullet as .45 ACP with higher velocity and less recoil and still fits in a regular frame. What's not to love about that.
I built a G38 for a customer last year and I almost bought it off him right there on the spot.