Picked one up on a whim, came in today. Did a quick 5 miler with all my multi-day gear to give it a whirl, love it. I recently cut down my regular Xlite pad to ~46" and was planning on using the sitlight pad that came with my Kumo to stick under my legs below the xlite when sleeping, but saw this air beam and had to give it a chance. I wasn't going to bring the supplied bulb pump with me but glad I did. Found I liked the AB a fair bit more underinflated then I initially anticipated. I'll now use the AB below my pad. It'll be a much better fit as the lumbar section of the AB is about an inch and a half so makes for a fairly smooth transition from bottom of xlite to it; far more agreeable then with the sitlight. As far as the ABs function as a pack frame, so much comfier then the sitlight. The sitlight has been fine really with my packed weights of ~15lbs, but regardless of how I packed my bag it still felt like I was carrying a cylindrical tube. The AB flattens it out very well, and has larger baffles along the edges going down your back, and also a cluster of larger baffles that hugs the lower small of your back. Like mentioned, when I made this impulse purchase I had no intent of carrying the inflation bulb with me, but I enjoyed being able to quickly deflate or add a little more air throughout the hike. Much like tightening/loosening straps to redistribute pressure points and weight every now and then. The complete setup weighs 2 ounces more then the foam back pad I was previously using, but since I cut off 4.5 ounces off my xlite we'll call it good. Some times comfort trumps weight.
Anyways, before I purchased the AB I couldn't find any info or reviews on it so maybe this will help some folks out who are considering picking one up. I thought it would be gimmicky and partially hoaky but I really, really like it. It hugs the back exceptionally well, makes the frameless bag actually feel like it has a frame, and the weight penalty is not terrible.