This was the "two season" version - I would want the three season version. The differences are pretty big. There are actually five different versions of this bag. They are 600 and 800 fill down options in both 2 and 3 season, and a women's version. So comparing the 600 and 800 fill down three season versions which is a 17º bag, the 600 weighs 3 pounds 1 ounce, versus the 800 fill weight of 2 pounds 10 ounces. 17 liter packed size versus 12.4 liter pack size. And the price for that 7 ounces? $100 ($319 vs $419)
These are not inexpensive bags. For reference, I am currently using an REI mummy bag that weighs 2 ounces more than 800 fill, $419 version, and it only cost me $159! This bag is more than double the price, with a treated duck down that I am still not sure how it will perform in a wet environment. But the fact is, no one cares about the fill. Or the weight, or the packed size. They care about the fact that this sleeping bag doesn't have a zipper!
So if you haven't read about this before, the Sierra Designs back country bed is mummy in shape, but the top half is very roomy. the feet, not much wider than a regular mummy. Instead of a zipper running down the side, it has a large opening in the front. With a blanket that is connected at the bottom of the opening. You get in the opening and tuck in the blanket and go to sleep. Want to roll over? Go for it, you will sleep in it just like a bed. Before getting in it I checked out all its little odd features, and there are many. Here are a few:
It has these funky mitten pockets in the top of the blanket. You may think it is to keep your hands warm, but really it is to make it easier to tuck in the blanket.
It has a pocket on the bottom to slide a sleeping pad into, so you don't slide or roll off of it. Sort of like a Big Agnes bag, but with insulation.
It has an opening on the bottom, near the foot, so you can open it, and/or let your feet out, if they re too warm. So how does it feel? That is a good question. It feels awesome! I would love this bag, and I wasn't even in the high priced one. It is beautifully made, clever AND intelligent. It is true out of the box thinking. I would love to give it a shot, but alas, I can't really justify $419 on a sleeping bag, even though a sleeping bag purchase is in my future. There was one nagging thought that stuck with me, as I was taking pictures of it....
Here it is with the blanket pulled all the way back - I do wish the blanket was removable so I could have the options of different weight blankets for different temperatures - As I looked at the bag on the table, it looked somehow familiar. And then it dawned on me. It looks kinda like this guy!