I just received my CK E2 grip today, because for various reasons I couldn't get a PT Evo. The profile lets me access the mag release without flipping the gun, checkering is better than pretty much any carbide coated plastic grip I've felt, with the exception of perhaps some super low grit carbide coated units. I was a little worried about the compatibility of mag buttons but mine fits and works perfectly.
I've heard gun smiths say that a grip that fits straight up, without any work, is not actually fit properly. When I spoke to Matt he said that the grip screw bushings should ahve to be drawn into the holes by the screws, and the front trigger guard screw should push in.
Either way I'll be pleased once I have fit mine up.