Being a complete and utter cold-arse I was lured by the -18 boast on the Lamina 0. However, I have struggled to stay warm in this bag. I am female, 5ft 3" and relatively small and slim. I was out in the tent last night 25/03/2012 in the Peak District, where there was a frost. Having recently purchased a 2" thick therm-rest type mat, I was extremely disappointed with the overall performance. I slept, fully clothed, in jeans, socks, RAB micro-hooded fleece and an OR jacket and was still terribly cold. Now admittedly I am a very cold person, but my other half slept snuggly in his (old) Firewalker 3. I could be unduly, harshly judging this bag, and maybe I'm sleeping in a man's bag and not a women's specific, therefore not generating much heat, could pose a problem for me.
Overall the bag is of good quality, although I struggle with the zip as it always catches. It's light-weight, and I expect if anyone else slept in it, they would say it's toasty warm.