neo air all season
I have the neo air all season, and using it in the BMBH sleeve. It has an r value of 4.9 vs 2.5 of the regular neo air. It packs small and is pretty light. I have only used it into the low 40's and was plenty warm, but will see this fall how low I can go. I got the large version on sale for around $100. I think new they around $180, so at that point your are pretty close to getting a underquilt for the price. I chose this route because I wanted to be able to also use it in a tent when camping with my family, and keep me warm in a hammock.