butthead wrote on Oct 29^th, 2010 at 5:00pm:

Solus; "This year a friend convinced me to try an Exped. It has an integrated pump (not as hassle free as the thermarest but much easier than the Big Agnes). It is more comfortable than any pad I've used, but considerably more bulky than the Big Agnes. It is amazingly warm. On my last outing I had quite a few nights in the twenties but used the bag only as a blanket- to get into it was to roast. " Could not agree more! The Exped 9 makes the optimistic BA temp  ratings closer to reality.  The combination of the Exped9 and a BA Lost Ranger is good to 20 degrees for me. With the Insulated Air Core BA pad I was chilly at 40. butthead

BH? Same tent (volume of space to heat) and time of year (similar ground temps)?

Specs I found, Thermarest TrailPro @ 2" and ProLite @ 1.5" thick were the same r value 3.8. With the BA Insulated AirCore only slightly warmer r value of 4.1.
Exped DownMat r values are much warmer, 7cm thick (r 5.9) & 9cm thick (r 8).

But I think the old standard Thermarests are fool proof too.

I've heard of failures for Exped too. One guy I know is on his 3rd one. Another guy swears by his BA Insulated AirCore, but he had to rig a bag type pump. So where's the big weight savings then? More comfortable, maybe,,,pack space, yes. He did notice what he thought was a leak, but was really just an air temperature change. Same as airbags in a whitewater boat after hitting cold water and later re-inflating tight in the warm sunshine.

I picked up a 15 deg BA bag and I guess I'll need to do some pre-trip experiments. From what I've read online, sleeping bag temperature ratings are standard from brand to brand. The material against your skin can feel very different though.