California, The Pacific Northwest
I had this pad and I can say that I was not happy with it. I felt like I was sleeping on PVC tubing. I let some air out but was still uncomfortable. I switched to a Big Agnes Two Track and was much happier and more energetic
This pack is great, I use it daily. I just wore it for a day up in Sugar Bowl and I kept forgetting I had it on - I was reminded when I got on the lift. It's very comfortable - the straps fit around me great (I'm 6'2" and have a 34" waist), and the stiff back conforms great to my movements.
My only gripe is that the zipper on the goggle pocket is tough to open with bare hands, let alone with gloves. I've had it for a few months now and it hasn't given any, so we'll see.
My girlfriend has a Thermarest Prolite 3 and this is comparable. Just as comfortable, durable, but less packable since it doesn't fold in half. If it was more packable, it would be 5 stars easy.
I'm really, really pleased with this bag. I was too hot in 30F weather. I actually had to switch bags with my girlfriend who was cold. She loved it too.
I prefer the Two Track pad to the Air Core series. though they don't pack as small, I feel they're a lot more comfortable.
I use this as my everyday pack. It fits my 15" MacBook Pro perfect (with a sleeve, too), carries books, shirts, whatever you need.
The pouch for a hydration pack is great when heading out for a day hike.
Lightweight pack, comfortable, flexible!