I purchased my XDM-9 in December of 2008 and so far have been pleased in it's performance. So far I have just over 3000 shots fired and it has not choked during "normal" firing. I had some issues while shooting from retention with some 115gr FMJ but shooting with 124gr+P JHPS resulted in no issues.
While the gun is on the large side, it is not the mammoth that some make it out to be and is not "too big" to carry concealed if one is determined to dress around the gun.
While I don't have any pictures of me concealing the gun, here are some reference pictures so show actual size of the gun.
These are taken from a post on HandgunForum.net:
So one of the reasons that I was hesitant about picking up the XDM is that a lot of people were commenting that it would be too large for CCW, I compared them in store to several guns that I carry on a routine basis and in some cases it was smaller, but in the few cases where it was larger, it wasn't much larger.
Here's some pics I took this evening, you can get a general idea of dimensions from the mat.
Note that I align guns by the trigger guards, when you think about it, it's basically the one aspect of most guns that are similar and gives a better visual of actual size difference.
Now up until recently, my main carry gun had often been a 5" 1911, while the XDM has over twice the capacity of a 1911, size wise it's actually smaller than my Les Baer as shown.
(Sorry about the finger, but due to the slide profile of the "M" slide, it liked to tilt grip up when laying down)
I didn't do a side by side as the Kimber should be darn close to the thickness of the other 1911 pictured, the only difference might be in the grips, but not much. I also didn't think to get a side by side of the J-Frame before packing it back into the safe.
Side by side, standard thickness grips on the 1911.
The "M" is not as thick as I thought...
Here is the "M" along with my Hi Power, the HP is actually a bit longer than the XDM.
And side by side, the XDM and the HP.
And as we all know, it's the grip that's hardest to conceal, right?
Well here's the XDM along with my HK P7.
Now while the P7 is considerably smaller, most of that is due to the low bore axis allowed by the gas system and recoil spring being around the barrel.
Again, side by side to show thickness.
Without doing an actual measurement, it appears that the P7 is a little more narrow, but remember that the P7 is a single stack 9mm with a capacity of 8+1.
Next up is the Sig 229 and the "M"
Forgive me, but while I do have a pretty good collection, the best I could do for this comparison is a "Blue Gun" from Ring's.
OK, so now what about some smaller guns?
Here are the "M", a 3" Kimber and a S&W J-Frame 360.
Now while many still won't carry something of that size, you can see that it's not that big, over all it's in the same size class as the Hi Power(13-15 rds.), the Sig 228/229 (13rds), full frame 1911s (8rds), I'd like to get a G19/23 for size comparison, but that will have to wait.
Overall I don't think concealment will be an issue, I can hide the XDM-9 with the included paddle holster under a vest, so once I get my IWB I think it will hide the same as my current carry guns.