Western Mountaineering MegaLite Review

Even with competitive recent additions, the MegaLite still rises to the top. It accomplished this with few, if any, changes from its previous versions. Why change what's perfect, right? In all seriousness, the MegaLite now faces stiffer competition than ever. We still love its spacious dimensions, low weight, and cozy warmth. However, if minor issues with the zipper and hood aren't addressed, it could eventually lose its throne.

Performance Comparison

Warmth

The MegaLite is filled with down advertised as "850+" fill power. When comparing it with other bags, however, it's important to understand that its fill power is a conservative estimate. Western Mountaineering claims the actual rating of their down is "almost always above 900." They report the lower 850+ number to be on the safe side and indicate the level of loft that's expected once the down is slightly compressed within the fabric of a sleeping bag or garment. In our tests, the 13 ounces of down inside this bag felt every bit as lofty as bags with reported fill power over 900.

Although Western Mountaineering doesn't publish EN numbers on its website, they are on the foot tag of the sleeping bag. The MegaLite has an EN Comfort rating of 32°F and an EN Lower Limit rating of 21°F. This makes it ideal for pushing the boundaries of "summer."

Ultra-premium down bags, like the MegaLite, offer versatility advantages due to their continuous horizontal baffle construction. This means the down insulation is contained within fabric tubes, or baffles, that are perpendicular to the length of the bag. These baffles are called continuous because they're uninterrupted by seams or stitches. This design allows you to move feathers to the top or bottom of the bag, depending on conditions. On cooler nights, shifting feathers to the top will trap additional heat. On warmer nights, you can do the opposite to avoid overheating.

This bag doesn't have a full draft collar found on other models. While this certainly isn't a deal breaker — it helps keep the bag light — backpackers who won't fill out all of the internal space might find it a bit drafty on chillier nights.

Weight

The 6'0" size we tested weighed in at an impressive 1.5 pounds on our scale. This places it close to the front of the pack. When you also factor in its considerable warmth, it results in an impressive warmth-to-weight ratio.

The comfortable, wide dimensions, however, do require additional materials. We've tried a few slimmer primo bags that can achieve similar warmth while weighing a few ounces less. The stuff sack Western Mountaineering includes with the MegaLite is light at 1.6 ounces, but there are other sacks that weigh half as much.

Comfort

The characteristic that ultimately nudges the MegaLite past its competitors is its comfort. With several extra inches of upper body girth, even our largest testers didn't find this bag constrictive. Our lead tester is slim and a life-long side sleeper. He found plenty of room to roll over inside this sleeping bag. Although this adds a few ounces, the added weight will be worth it for most users, especially when you consider an ultra-premium down bag can maintain its loft and performance for a long, long time. Think about it — ten years from now, might you find yourself appreciating the extra room?

Another subtler aspect of MegaLite comfort that distinguishes it from its closest rivals is the shell fabric. All premium bags feature shells that are soft and weather-resistant. However, we've noticed that some can also be strangely noisy, with at least one tester complaining that the crinkling sound of Pertex Endurance fabric disturbs their sleep. No noise issues were observed with the ExtremeLite fabric found on the MegaLite.

Packed Size

In our tests with an aftermarket compression sack, this bag compacted to a respectable packed volume of 7.2 liters. Although this wasn't the smallest size we saw, it is the smallest for bags that provide a similar level of warmth.

To take advantage of this benefit, however, you will need to purchase a third-party compression sack. The simple drawstring stuff sack that comes with the MegaLite does an OK job at compression but will still leave you with a bag that occupies a couple of extra liters in your backpack. It's also worth mentioning that the included stuff sack is not waterproof. If your travels take you to the rainy Northwest or perhaps paddling in the Boundary Waters, you may want a waterproof storage option.

Features

All of the Western Mountaineering bags, including the MegaLite, feature a flexible internal strip of plastic along the length of their zippers. This strip gives the fabric next to the zipper critical stiffness, preventing it from snagging. The other thing we like about the zipper on this bag is how far down the side of the bag it runs. This let us open the MegaLite really wide to use as an improvised quilt for two. It also let us have some targeted ventilation on stinky feet. Western Mountaineering zippers could be slightly improved, however, by incorporating anti-snag slides and an internal pull tab.

Another small issue is the hood. It is anchored at the zipper closure with a weak piece of velcro that felt awkward to use. When cinched tight, the hood only provided below-average comfort.

Should You Buy The Western Mountaineering MegaLite?

The MegaLite is a fantastic sleeping bag, especially for backpackers who are trying to strike a balance between a light pack and sleeping comfort. For dedicated backcountry travelers, the performance benefits of this bag are worth the premium price. In our experience, premium down holds up better to being repeatedly compressed than lower-quality down or synthetic insulation. This means that over the full lifetime of a bag, a MegaLite could ultimately be cheaper per use than some lower-priced bags.

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