Rating: 5 / 5
Ok, I'll admit that I'm posting this review just to see what it does to my BPL rating. Oh the vanity!
I bought this bag sight unseen, based largely on Western Mountaineering’s reputation within the backpacking community. I'm sure this isn't uncommon as there aren't many retailers that stock WM's products. Also considered at the time of purchase were the Feathered Friends Hummingbird, Marmot Helium, and Moonstone Lucid, and a few others. All were around the same price so when I settled on the Ultralight it was because I felt it offered the best set of features of all the bags I researched and was made in the USA to boot. The bag comes with a large cotton storage sack and a 7x13 nylon stuff sack.
I've since spent about a dozen nights in the bag, my wife an additional 4-5. Temperatures have ranged from 60 degrees F down close to the bag's suggested limit of 20 degrees F. Conditions have ranged from clear and dry to humidity so high that thick fog didn't lift all night.
Materials and Construction: My first impression of the bag was that it is very well constructed. I have no reason to believe I will form a different opinion over the years that I will own the bag. All of the stitching is impeccable. The materials are well selected. The shell fabric is thin and, while it beads water very well (I never have to worry about condensation or the occasional spill), it does allow strong wind gusts to penetrate the bag. I can compensate for this with my shelter, however. Overall, the Ultralight might be the best engineered piece of outdoor equipment I own. The only quality issue I've had was when the stuff sack's draw cord became fouled in its plastic barrel lock. A sharp burr on the lock caused the woven cord to fray. WM immediately shipped me a new stuff sack at their expense.
Fit: I bought the medium, sized for those up to 6' tall. The Ultralight is cut slim to save weight. It's the slimmest cut mummy bag I've ever used but I like the tighter fit as it gives me an extra little feeling of security. I'm 6' even and 200 lbs with fairly broad shoulders. If I were any larger in girth, I would probably have gone with WM's Alpinlight which is essentially the same bag, cut slightly bigger. As it is I have just enough room to wear my Patagonia Micropuff in the bag without compromising the jacket's loft. My wife at 5’8” and, ahem, average weight, fits in the bag comfortably without too much extra room to warm up.
Weight and Packed Size: Tips my scales at 26.5 ounces, just 0.5 ounces heavier than advertised by WM. I hope that additional half-ounce is extra down filling! The stuff sack weighs 1.8 ounces. I have never compressed the bag smaller than the provided stuff sack but I have no doubt it would fit into a sack smaller by several inches in each dimension without much effort required.
Loft: Tricky to measure consistently but close enough to the 5 inches advertised to make me happy.
Features: Western Mountaineering calls the bag the Ultralight 'Super' in reference to the full 'super' draft collar. This down filled tube lines the top opening of the bag and securing a small velcro tab connects the tube’s two ends, sealing the bag from the neck down. The draft collar can be cinched tight via a thin elastic cord threaded around the collar. This feature does a great job of extending the bag's temp rating as there is no 'bellows effect' of warm air escaping as you move inside the bag. A real plus! The bag has a full length, two-way zipper (making foot venting easy) accompanied by a draft tube. I'll go ahead and declare the zipper snag-proof. I tried purposely to snag it and, due to a generous strip of stiffening tape lining the zipper, I couldn't get it to catch the bag's fabric. It's by far the best zipper on any bag I've used. When fully zipped, the zipper pull can be covered with a small velcro patch but I've never observed the zipper to move during the night. The bag's full hood also has the usual draw cord closure. Both this and the drawstring included in the draft collar are well-placed and easy to operate in the dark. The Ultralight is continuously baffled which makes it easy to shift the down around as needed. In warmer conditions, the full length zipper makes it possible to use the bag as a quilt.
Performance: This is where the bag shines. I've never had the bag below 20 degrees F but I have no doubt that the Ultralight would be sufficient into the teens and colder with some additional clothing. In temps down to 30 degrees I wear no more than thin tights and short-sleeved shirt and have never been cold. Only when temps drop into the 20's have I added a hat or long-sleeved shirt. As stated previously, I'm sure the addition of gloves, heavier baselayer, and an insulating vest or jacket would get me down into single digits tolerably. My wife, predictably, places the comfort rating about 5-10 degrees higher than I do.
Dislikes: My only gripe about the Ultralight is the hood. It's a bit shallow and could use some minor redesign. I feel it fits awkwardly across my face when fully cinched. I'd gladly suffer the weight penalty to have a down-filled face muff similar to the one on Marmot's 800+ FP down bags. The hood is warm but I don't feel the design is up to the extraordinarily high standard of the rest of the bag.
Summary: I love it. My favorite piece of gear. Since I can't quite bring myself to make the jump to quilts, I feel the Ultralight Super offers me the best set of features in a dependable, super-lightweight package. With Western Mountaineering's reputation for quality and durability, I know I will be using this bag for many years. I have difficulty finding anything other than minor nitpicks with the bag as a whole. The one exception is the hood design, which might make me select a rating of 4.5, were I given the option by BPL.