I'm looking to purchase a new sleeping bag. I previously had the North Face Cat's Meow 20, but I need something warmer than that. The two bags that I have in mind are the REI Magma 15 and the REI Down Time Zero. I'm wondering if anyone has any experience with either of these bags? I'm leaning towards the Magma, because it is less than two pounds vs. the Down Time 0, weighing in at 4lbs. Anyway, I went horse camping in the Sespe, and I was freezing cold in 40-degree weather (I was sleeping without a tent). I have an REI Flash 4-season inflatable pad, so I don't see a problem there. My main concerns as of now, are: staying warm and weight. I went to REI to try the bags out (they only has the Magma), and I was very surprised by how warm the Magma was. Even though it's only a 5-degree difference in *advertised* ratings, I immediately felt it. Those are my thoughts, so if anyone has any advice, that would be greatly appreciated. New to Reddit, so if I messed up with post format or anything, my apologies.