I don't know much about them, other than what I have read. It sounds like they have helped in some cases, as have AvaLungs.

In general, I think anything that improves your odds of survival is probably a good thing. However, what I don't like to see is when people think a new peice of gear makes it OK to do dumber things. (I'm not accusing anyone on ETS forum of that, by the way. ) I try to view gear like beacons, AvaLungs, etc just like seat belts in my car. They are a back up in case I make a mistake or have bad luck, not an excuse to drive faster.

By the way, I'm sure you know this already, but when snowmobiling, make sure you cary your rescue gear (shovel and probe) on your person, not strapped to your machine. You don't want to find yourself lying on top of a slide, with your buddy buried, and you can't dig him out because your machine and rescue gear are also buried.

Have fun in the snow, but stay safe.