Someone posted that over at XDTalk a while back. While I realize it's just a prototype, I'm not impressed. To me, it looks like it would interfere with gripping the gun and isn't very aesthetically pleasing.
If I were going to equip my XD with a laser, I'd likely go with the internal LaserMax.
http://www.lasermax.com/category.php?id=7
I'm not all that keen on lasers, though. I believe they have limited benefits outside of training and are expensive. I'd rather spend the money on new guns!