I purchased one a year ago and I absolutely love it! I have the 4" service model in 9mm OD green (
XD-9 OD )
The only problem I had with it was with the magazine. You can tweak the magazine lips for the .40 and use it as a high-cap for the 9mm. The place I bought it from gave me a .40 mag instead of the 9 and I didn't want to try and tweak it myself and screw it up. I got the original mags and it has rocked ever since.
Thw link that rubberneck provided is good. Also check out
XD Gear