The only flaw I see is the claim of 3-4 R-Value for such a thin pad.
I'm wondering how they get an R-Value of 3-4 from a .39" thick closed cell pad. In this thread, Richard Nisley states that the typical R-Value of a 3/8" (.375")blue foam pad is 1.35. I'm not an engineer, and I realize there are construction techniques that can increase R-Value over the generic blue pad, but to practically triple it? For 9 oz? I have a full-length Thermarest Ridgerest that I've trimmed to mummy-ish dimensions that now weighs 9.28oz, but is ~60% thicker at .625" and Thermarest is only claiming a 2.6 R-Value for it.
Claims aside, I like the idea of a CCF for warmth + NeoAir for comfort winter sleep pad system. I haven't done a lot of winter camping, but one of the things that holds me back from a downmat is the possibility of a leak. If it leaks you're on the ground. If you need to bring a CCF as a backup for safety, that's just increasing your weight. And you'll need at least a a sit pad sized CCF to sit on, and preferably one for under your feet, so why not use the same one as part of your sleep system and top it off with a comfortable NeoAir?
That's why I'm intrigued by the Ridgrest Solar discussed in this thread.
If I can get close to the same 34% weight reduction I did trimming my standard Ridgerest, I could get the Solar down to 12-13oz, combined with my small NeoAir for a weight of 22oz with an R-Value of 6 under my torso and hips, and an acceptable 3.5 plus whatever my pack adds under my feet.