I like the innovative design. I am a warm sleeper in general, so needed a bag that could be a good Sierra summer bag. So far on only two trips this bag has done well. I like the way I can adjust the temperature as needed when I get to my destination by turning it this way and that way. Wish it would pack a little smaller. As it is likely only a summer bag, a down version would be great to save weight and size, but this is pretty small as is. Seems well constructed and roomy. I am 6'1" and the tall fits me well. Might be nice of them to add a small mummy head portion that you could use if needed, but if it gets that cold a hat will do or a heavier bag.