I'll have to check them out- I'm not in the market for any more cans, but the technology sure looks interesting.
I've also come to the conclusion that when shooting .308 (standard velocity and .223/5.56 for that matter), a few decibels difference between different manufacturers is meaningless. The super sonic crack of the round is so loud, it doesn't matter what the can is doing.
I can appreciate technology if I'm looking for another can I look for weight, repeatable POI, $, then sound that's what's cool about the K or modular cans now is that extra option I like it. The trees will let you hear that sonic crack real quick to I've noticed in the woods.