A couple of years ago I was looking at buying an Alpkit Pipedream 400 but despite checking the website on numerous occasions they never ever seemed to have anything in stock 
. I gave up on them in the end and bought a Rab Quantum Endurance 400 at a reduced, sale price.
Having now used the bag on many, many trips, I couldn't be happier with it and would certainly buy the same again. It's rated down to -5 degrees. The lowest I've used it is -4 degrees with just a Thermarest Prolite 3 Short underneath and a good layer of snow below that 
. Sleeping in just a thin polyester t-shirt proved perfect and I was comfortably warm, never once feeling cold.
The dryshell coating is superb also. Having slept in the open out of the tent on several occasions. I've woken in the morning with the bag completely covered with dew and it remained totally warm and kept all the moisture on the outside of the bag.
