I have a XDm 5.25 and also agree about the grip not being comfortable and found that it moved around too much in my hand which in turn made the accuracy suffer. I installed the PRP grip and it's a totally new gun literally. It feels fantastic and doesn't move a bit. I suppose the PRP match trigger I installed helped with the accuracy too but it definitely made the gun worth keeping. Last time out it tore the center of the target out.
X-Treme Grips for XD/XDM