Just because a piece of gear did the job for you does not necessarily mean it will do the job for everyone. That's especially true of insulation, because physiology and metabolic rates vary widely among individuals.

For example, look at the EN13537 ratings for sleeping bags. This is one of the few objective standards around for rating warmth of outdoor gear, although it applies only to sleeping bags. Page down on the above URL and you'll see a colored diagram showing the difference between the "comfort rating" for the "standard woman" (whatever that is) and the "lower limit" rating for the "standard man" (whatever that is). I prefer to translate these terms as "cold sleepers" and "warm sleepers," since I know men who are cold sleepers and women who are warm sleepers. The diagram shows that the difference between the two ratings is 5*C or approximately 9*F.

I owned a Marmot Hydrogen sleeping bag a few years ago and started getting cold in it when the temperature got into the upper 30's, even though it's rated at 30*F. Now that Marmot is using EN13537 ratings, it's easy to see why. The rating for men (translate "warm sleepers") is 29.8*F. The rating for women (translate "cold sleepers") is 39.2*F. I am definitely in the "cold sleeper" category, and these ratings explain quite well why I had to start wearing extra clothing inside the Hydrogen with the temperature in the upper 30's. By the time the thermometer got down to 30*F, I had all my insulating clothing on inside the bag to keep warm. When the thermometer dropped into to the mid 20's, I was shivering with all my insulated clothing on (and I had a lot of it; I was expecting those temperatures). According to the EN13537 ratings, that's exactly what should be happening. Evidently I fit the profile of the "standard woman" used for these ratings, so I'm not, as I once thought, an unusually cold sleeper.

Apply this 9*F difference between warm and cold sleepers to the NeoAir, ostensibly rated at 32*F, and you have the explanation why I started feeling cold underneath when the temperature dipped to the upper 30's. I had to use a supplemental CCF pad, which of course canceled out any weight savings of the NeoAir over the insulated air pad I had been using, which for me was comfortable to the low 20's F.

The "standard" used for the EN13537 ratings is, of course, an average, which explains why some individuals are comfortable with a 32-30* F sleeping bag or pad when the temperature is down in the mid-20's. There are undoubtedly some individuals who start feeling cold in the mid 40's F with identically rated items.

I also found the NeoAir uncomfortable, which was the other reason I returned it after 6 months of trying hard to make it work. The whole experience was a really good lesson for me about NOT choosing a gear item based only on its light weight! With its small horizontal tubes, I never could find the "sweet spot" of inflation between lying on an uncomfortably hard surface and having my hip bones hit the ground when I was on my side. I also kept rolling off the thing any time I got close to the edge. I've read that this is the most common complaint about the NeoAir--it feels narrower than other pads because the outside edge collapses when the body gets close to it. These findings are, of course, subjective, so again will vary widely with individuals.

The above experience, as well as the temperature ratings, is why I caution about the NeoAir to people looking for air pads, particularly if they're going to encounter cold nights. It's definitely not for everyone, and for many of us it's a summer-only pad (for the Cascades, but not for the Rockies). The NeoAir is also a very expensive piece of gear to try out. Although I've often been unhappy with REI, with the NeoAir I was very grateful for their return policy!

It's wonderful that you are happy with your NeoAir. I'm not trying to invalidate your experience. Please don't try to invalidate mine. We are each unique individuals, obviously with very different reactions to cold temperatures!