The video above is from last year, but it was the only I could find of it actually impacting targets. The Army has deployed it to Afghanistan in select Special Forces units to get real combat feedback. Each unit costs $25K, and each round, $25 bucks.
It looks cool, but the soldiers did seem slow to fire it. Not sure if that was just for demonstration, or if it has some inherent complexity that slows them down.
Read more here.