i write this as someone whose previous bag was a cheap summer synthetic bag that may have been suitable for car camping in August, but wasn't good for much else. I nonetheless hauled that baby (and an extra liner) on many a backpacking trip, and just came to expect a chilly and uncomfortable sleep as par for the course. I just couldn't afford a good bag...
Until now. The Helium is by far the nicest piece of gear that I own (hooray for backpacking on a grad students' stipend!), and is a high quality item for which I paid a VERY reasonable price. It's a billion degrees warmer and more comfortable than my previous bag, is snug but not restrictive (I'm 5'10, athletic build), weighs barely anything, and packs down practically into a walnut shell. The zippers are smooth and don't catch, and the down is lofty as all get out. I think it is likely made from pixie hairs and unicorn breath.
Haven't had a chance to test this baby on the trail yet, but I am 107% confident that this will change my backpacking life.
Tl;dr: this might be too "heavy" (that's a relative term) for UL purists, or not warm enough for arctic expeditions, but if that's what you're looking for you probably weren't considering this bag (or reading this review) in the first place. For someone doing long trail miles in 3 seasons, however, (and someone who is by no means shopping in the ultra high-end market) this bag is an absolute dream....and an absolute STEAL at the (below listed) price that I got it at.
This review was written in the old system and had content requirements that are different than reviews written today.