In reply to neuromancer:
I have both the softie 3 and softie 9 (as well as a jazzy down mammut bag). Softie 3 was bought in 2002 and is still going strong, doesn't lose insulation like other synthetics and I expect the 9 bought in 2012 to last the same. I bought a North face synthetic bag in 2005 and only lasted 5 years as the insulation lost its loft and warmth; so Snugpaks are a good investment
However as per other comments, Snugpak are slightly optimistic with their temperature ratings.
For using on exercise year round in the UK, the softie 9 (teamed up with a fleece liner in winter) is probably warm enough for most things and is still more compact and lighter than the issued bags. Snugpak are sized for soldiers and have durable foot boxes for those days when you keep your boots on, can't go wrong.