If your budget lets you shop for the absolute best backpacking sleeping bag, you will likely end up with a choice between Western Mountaineering and Feathered Friends bags. You basically can't go wrong. But to help you out a little, the UltraLite sets itself apart with a legit draft collar that ensures you can seal all your body heat in on colder nights.
Performance Comparison
The UltraLite came close to winning our Editors' Choice but the review team ultimately decided that it's probably too warm for most 3-season users. However, it still earns our Top Pick Award as the best cold weather 3-season bags
Warmth
Although it doesn't receive an industry standard EN temperature rating, our testers believe the UltraLite is one of the warmest 3-season bags we tried. Its 17 ounces of 850+ fill power good down seem to supply slightly more warmth than bags with 20°F manufacturer ratings, like the Feathered Friends Swallow 20 YF and Marmot Phase 20. This superior performance is partly due to its substantial draft collar. When cinched closed with the internal drawstring, this collar was comfortable and effective at sealing heat inside the main compartment of the bag.
Some testers, however, consider the same collar to be unnecessary weight for most 3-season temperatures. Maybe so. But in colder spring and fall conditions or at high altitude, you won't have to worry about staying warm. The inclusion of the draft collar also arguably extends the UltraLite usefulness to mild winter applications.
The draft collar inside the UltraLite uses an elastic drawstring to snug over your shoulders and seal all your heat inside the bag.
Weight
Despite providing best-in-class warmth, this bag weighs in at an impressive 1.86 pounds for a size long. Although this leaves it near the of the backpacking sleeping bag field, it compares favorably with its closest 20°F competitor, the Feathered Friends Swallow YF. Another close rival, the Marmot Phase 20, does weigh two ounces less. To enjoy the weight advantages of that bag, however, you must accept less insulation and a shorter zipper that is prone to snagging.
In our view, the couple of extra ounces of the UltraLite are worth the weight. Finally, when you examine the warmth-to-weight ratio, this bag challenges the 30° Feathered Friends Hummingbird.
Comfort
Unfortunately, the UltraLite does not offer quite the same comfort as its outstanding Western Mountaineering relative, the MegaLite. Although it has the same cozy down and soft ExtremeLite fabric, its narrower dimensions don't provide the same spacious dimensions.
These dimensions, however, are similar to most of the other standard mummy bags we tried. The UltraLite would thus earn an average comfort score were it not for its gentle, cloud-like loft that caused us to give it an extra point.
The awesome loft and soft fabric of the UltraLite boost its overall comfort.
Packed Size
A common consequence of lots of warm insulation is a larger packed size. The UltraLite is no exception. Using an aftermarket compression sack we were able to squeeze this bag down to 8.7 liters in total volume. This gives it one of the largest packed sizes in this review.
Shoppers should keep in mind, however, that per liter this bag offers unrivaled warmth. Moreover, the difference between the biggest and smallest bags in the backpacking sleeping bags review was not especially large. When compared to its more distant competitors in the budget backing sleeping bags, the UltraLite and all the other bags in the standard backpacking review were relatively small.
The UltraLite's included stuff sack isn't great at getting it small. A third-party compression sack can get it down to 8.7 liters in volume.
Versatility
This bag owes its superior versatility to its horizontal baffle construction, a full-length zipper, and an effective draft collar. Horizontal baffle construction means that its down insulation is sewn into fabric tubes, or baffles, that are perpendicular to the length of the bag. These baffles are continuous which allows you to shift the insulation to the top or underside of the bag depending on conditions. On colder nights moving more feathers above your body will ensure more heat is trapped inside. In warm conditions, do the opposite and shift feathers below your body to allow excess heat to escape. You don't have the same option with vertical baffles or synthetic insulation.
The full-length zipper also gives you another way to vent excess heat and be more comfortable on warmer nights. The substantial draft collar, in contrast, can cinch comfortably over your shoulders to prevent drafts from drawing heat out on colder nights. Together these features result in a bag that has the flexibility to stay comfortable across a wide range of temperatures. Its only drawback in terms of versatility is its down insulation which is inherently bad at insulating when wet.
All "full-length" zippers are not equal. The Feathered Friends zippers (red) are noticeably longer than the Western Mountaineering (blue) or Nemo (orange) zippers.
Features and Design
Although the UltraLite lacks many of the fancier features of other bags, simpler is sometimes better. The absence of an organizational pocket or additional venting zippers helps this bag save weight.
Meanwhile, its only arguably unnecessary feature, a functional draft collar, is the defining characteristic that sets it apart from its closest competitors in terms of warmth and versatility. Thus, when you consider both the features this bag does and does not have, its overall design makes more and more sense.
The velcro tabs used to seal the hood and draft collar are slightly awkward to use and not great at keeping things closed.
Best Applications
This bag is ideal for passionate backcountry travelers that don't let a chilly forecast ruin their plans. With a good sleeping pad and appropriate precautions to keep it dry, it is suitable for milder winter nights. The substantial insulation, however, is sure to be too much for summer at lower elevations or more tropical latitudes.
The UltraLite may be too warm for hot summer nights but it's awesome for cold desert bivies.
Value
Western Mountaineering doesn't give the outstanding performance of the UltraLite away for nothing. With a list price of $525, this bag is one of the most expensive 3-season bags we've seen. For this price, however, you receive a quality bag that's made in the US of A. And like the other ultra-premium bags, we believe the high price of the UltraLite is actually a great value when you factor in the weight and performance benefits you get to enjoy over its 10+ year lifespan.
Conclusion
In a field filled with 800+ fill power down bags, the UltraLite stood out to take home our Top Pick Award for Colder 3-Season Conditions. It achieved this by offering best-in-class warmth in a bag that was also comfortable, versatile, and low weight. Its biggest drawback is its astronomical price tag. If cared for properly, however, it could last for 10+ years and ultimately become a decent value. So if you're in the market for a 3-season bag that's up for the harshest conditions, you can't do any better than the UltraLite. If your backcountry travels occur in tamer temperatures, you might be happier with the lighter MegaLite or Feathered Friends Hummingbird.
