Thomas:
devils advocate here… You dont feel that for 28 ounces your baiac should at least keep you as warm as your bag rating? You said you used a 15* bag as were cold at ~20*. For 28oz worth of pad you should at least be able to take your bag to what it was rated for. OK so maybe extreme cold its different but 15* aint that cold.
"I had one wish for this pad it would be an R value at 5+ and 8oz less weight."
-like, say, the xtherm? Basically you just said your pad is not warm enough and too heavy.
Also, letting air OUT of your pad will make it colder, not warmer.
think: thin down vs. puffy down.
Also, also, NEOs are thin, but not weak. There has not been the puncture troubles many thought would come up. Sure, they do puncture… so do car tires. but there isnt a problem with that happening under normal use.
…Not trying to be an ass.