The army sleeping bag is very warm, sometimes too warm for UK, the only real drawback is its size and weight. I found a lot of people using softie bags (smaller and lighter), used one myself (a softie 9) in Bosnia over the winter in 95 and found it very good. I did find a couple of draw backs though, the material is a bit fragile and after a fair bit of use and abuse it looses its thermal qualities, like most bags I suppose. I now have an Ajungilak bag which is sturdier, the same size and about the same price. You tend to find that if you want it in green then you start to seriously limit your options.
Brian