I actually really like the XDM. I was planning on getting the 3.8" compact....until I handled the mod.2. I took a handgun course on Monday and rented the XDM through the whole thing. It shoots great, handles well, and I didn't have a single issue with it. It would be a great choice, but that said, I no longer believe that it's worth the ~$100 extra over the mod.2. I was hung-up on it being able to hold 19 rounds instead of 16, but the grip on the mod.2 is phenomenal and the 4 inch model is the perfect size for me (almost identical to the glock 19). Plus 16+1 rounds of 9mm should take care of anyone with some to spare.
So, if you find an XDM for a good price, I would consider grabbing it. But the mod.2, in my opinon at this point, is the better XD option.