The Lifeventure is marketed more towards travellers. 100% cotton and has a bed bug coating that no alpine lover would ever need. The S2S Reactor's are awesome - not cotton, but hollowcore that traps much more heat than cotton. More $$ but I've heard great reviews from my employees. Another option is to get a reusable bivvy. This is what I have http://www.adventuremedicalkits.com/...hermal%20Bivvy
It kept me toasty in mid november w/0 a tent on the top of Golden Ears w/ only a -7 synthetic bag. They retail for around $40 so price is comparable to decent liners. Plus, it functions as part of your emergency kit too - much more practical than having a liner imho. Used on about half a dozen trips in the past couple seasons and wear&tear is fine.