Jason Livingstonwrote a review of Therm-a-Rest Antares HD Sleeping Bag: 27 Degree Down on April 4, 2017
Familiarity: I've put it through the wringer
I've used many bags over the years starting with Moonstone and eventually buying some of Marmot's higher end bags (currently own the Hydrogen). I've also slept in a Western Moutaineering Alpinelite, several North Face bags, Sierra Designs, Big Agnes, and Montbell. I bring to this review 20+ years of sleeping in really nice down bags.
Currently I own and use the Thermarest Antares. What I love about it is that it's super roomy. I have plenty of space to move around and get comfortable including bending my knees while the bag is attached to the mattress (something I couldn't do with a sleeved sleeping bag). In fact it's the first bag I've used that really accommodates me sleeping on my side. The reason is due to the design of the bag that doesn't create any dead-air space, something I've experienced with other sleeping bag/pad combo set-ups, when laying on my side. My biggest issues have been bags with 'sleeves' on the bottom that create a teepee effect which tends to open up the interior of the bag to cold air which I then have to heat up. I've experience many cold nights in sleeved sleeping bags in the past that haven't come close to their advertised temp rating.
The Antares uses an ingenious system (called Synergy Link Bands) that hold the mattress and positions it at the bottom so I don't slip off, but because of where they attach to the bottom, allows me to sleep on my side while the sides of the bag come in to my body. It works well and I can't remember a time when I've been cold. I also love the fact that the zipper is in the same position in the morning that I started the night in. I've had countless nights sleeping on top of zippers that I don't want to replicate.
The other thing I love about these bands is how easy it is to attach my mattress. A mattress sleeve can be difficult, but the bands allow me to get my bag set up in minutes. It's awesome!
I love the packability and weight of the bag for it being 20F. I've also noticed the heat reflective materials that help warm me up rapidly. The hood is shaped well and when needed I'm able to really snuggle in. The draft tubes are large and keep cold air out. I also love that it doesn't have velcro anywhere near the skin on my face, something that really bugged me with the Western Mtneering bags. It's a sleeping bag I'd recommend to anyone! I love mine.