So I have a KGMR556 can and an R30T in jail. I haven't put a lot of rounds through the 5.56 can, but I've been very happy with it. Suppression is good. I like the sound signature. Not much blowback. And I like the attachment system. The fact that they seem to have some big gov. contracts gives me some confidence that they will be around for a while and that their cans will prove to be pretty rugged. Yes, they did make the DA Sierra 5, which has had problems, but they also made the Sandman for DA, which has proven to be a solid hard use can.
Plus, at the markdowns these cans have been selling for they are hard to resist. Picked up the 30T for $400, and the 5.56 for $170 plus $5 shipping directly from KGM.