I use this bag when backpacking, and it has worked great! It is warm, light, and durable.
A great feature is the synthetic down they use. Unlike natural goose down, synthetic down can get wet and still keep you warm! So, you may gain a little weight with the synthetic, but if you are in a high moisture area it is definitely worth the extra weight.
Lastly, you can't beat the bang for your buck
This review was written in the old system and had content requirements that are different than reviews written today.