Purchased this bag knowing full well that synthetic fill bags don't compress very small. Planned on using it with an external frame Kelty pack strapped to the outside. Purchased the Alps "cyclone" compression sack size M to go with it (btw, this is by far the best compression sack I've found, but that's for another review). Given the high loft and generous fit, I was surprised to actually be able to stuff it into the bag compartment of my internal frame pack. Works with mine, but can't guarantee it will fit in yours.
As I said, this bag has a more generous/spacious fit than most mummy bags. Finally a mummy that doesn't make me feel claustrophobic. Once it's had a chance to expand, the bag/loft is fairly thick. Haven't put the temp rating to the test. I've used it almost exclusively Spring, Summer, and Fall. I didn't freeze at 40 or sweat at 65. Did spend one night in it below freezing, but I was wearing a level 7 ECWCS primaloft suit so that doesn't really count.
As of now, I got about 30 nights in this bag and aside from some dirt, it looks brand new. So far it's wearing well. I do store it in a large tupperware so it has plenty of room to breath. Did get the zipper stuck once, but was able to get it undone. The hood and draft collar work pretty good. It zips from both the top and bottom. 3lbs 12oz isn't bad considering the size of this bag and that it's a synthetic fill. Have 20F down bag that is a lb lighter and compresses a good 30% more, but it also cost 5 times as much and takes forever to dry out.
This bag is very good quality for the price. Not for ultralight backpacking obviously, but good for most purposes. I like it so much that I bought the -20F version in XL wide for hunting season, but that one is big enough for 2 of me and weighs a lot more. Not something I would ever pack.