While I'm a fan, I'm also worried about the durability of it as far as a tarp application. While at the ohio hang there were stories about acorns falling and putting holes in a cuben tarp.. I immediately thought, what's the point of shelter if it's so delicate it can't deflect an acorn? I need lightweight DURABILITY for most of my gear that's not sleep gear. While I'm very impressed with the weight of it and the waterproofness (and I actually like the transluscence) I've also heard the mylar (the cuben fiber is bonded by mylar as I understand it, so it's really a bunch of fibers on/part of a sheet of mylar) breaks down over time.. How long is what I'm itching to find out. $400 is a lot for a piece of gear that'll only last a few seasons.
But as of now, they're getting good marks. Fella's did an overnight here in ohio and got some good winds and reports were all good so as far as right now, it's a pinnacle fabric for backpackers.