Third posting about these pads, and this time it's positive! The second NeoAir XLite held air just fine! I've changed my ratings here and on Backcountry.com. My sincere apologies to Therm-a-Rest for my post on the second pad - I was too quick to judge given the disappointment with the first pad.
As near as I can determine, here's what happened:
Whenever I get a new pad (inflatable or self-inflating), I blow it up to maximum inflation, and set it in a narrow alcove of my office/gear room to check if it holds air. The first pad went down very quickly, and my disappointment went up as the pad went down.
The second pad went into the alcove, and after 24 hours seemed pretty good. The second day it appeared to be slumped down somewhat, maybe a fourth of the way down the wall of the alcove. "Dang! It must have a slow leak!" thought I. And proceeded to post such again.
But now, nearly a week later, it hasn't "lost" any more air. Odd! What's up?
Somehow, the bottom of the pad got moved from one side of the alcove to the other, causing it to appear to be slumped down as if it had lost air. Given my history with the first pad, I was too quick to blame the change on the pad, and did not notice the change in position. I only noticed that distinction today.
The change in position I blame on my dogs! They seem to think the alcove is a great place to curl up for a nap. My failure to notice the difference in positioning I can only blame on myself.
Mea culpa, mea culpa, mea maxima culpa! (For the classicists among us)
Bottom line: Very nice light weight pad, lots of comfort (thickness) for low weight. My BPL review now rates it a "5".