Yeah, when I was in the army we got these paintball guns and opened 'em up so they'd REALLY hurt. Maxxed out. The idea was to teach us to take better cover but it just ended up with everyone trying to get as close as possible to do as much damage as possible and everyone wound up with bleeding bruises (one guy has to go to the hospital!).
The only other experience I have is with Simmunition but we didn't get to use it much before the unit deployed. It looked real promising though. Don't hear of it all anymore.
I think this thing looked cool because their army puts it on and I bet they put a lot into it.