Just back from a weekend in Wales (UK), using this bag. I was skeptical about not having any insulation beneath me, but it worked a dream (using a thermarest pad, rather than BA). I slept like a baby. I really like the fact that the bag doesn't ruck up or twist around you. Also (using the grey-black colour way), it blocks loads of light. I woke up 2 hours after dawn and couldn't believe it was so bright when I emerged from the bag. Normally, I'm up at dawn. One word of warning: the stuff size is after compression. Some other bags have a stuff size before compression, so it's not a true comparison. This bas is much bigger than, say, a mountain hardwear phantom bag in its stuff sack which can't really be compressed any further.