As its name implies, the Merlin is almost magical for the warmth and comfort it provides in such a lightweight package. Although it ultimately lost out to the Western Mountaineering Megalite for the Editors' Choice Award, it still deservedly earns our Top Pick for Light and Fast Adventures. The competition between bags from these two manufacturers is so close that it's vital to weigh the pros and cons of each to ensure you pick the perfect bag for you.
Recording our thoughts during a field test with the Feathered Friends Merlin.
The Merlin UL contains 12 ounces of ultra-premium, 950+ fill-power, goose down. Although this is an ounce less insulation than its closest rival, the Western Mountaineering MegaLite, it has a narrower fit that requires less material to provide the same amount of warmth. Both makers give their respective bags a temperature rating of 30°F.
In the field, our testers were unable to detect a warmth difference between these rivals. Compared to other bags that are EN tested, we felt the Merlin provided a similar level of warmth to the average bag that receives an EN lower limit rating of 20°. With this level of insulation, it's an excellent middle-of-the-road bag that's well-suited for all but the coldest or warmest 3-season uses.
The Merlin's 30F rating is generous compared to other bags. We think it's warm enough for cold spring and fall nights.
Weighing in on our scale at 1.45 pounds for a size long, the Merlin UL is truly ultralight. This is made all the more impressive when you consider its substantial insulation and sturdy, full-length zipper that provide significant warmth and versatility, respectively.
On paper, the Therm-a-Rest Hyperion 32 would seem to offer an even better warmth-to-weight ratio—it weighs 5 ounces less but is given a temperature rating only 2 degrees higher (30° vs. 32°F). However, our testers found the Merlin's insulation to be much warmer than its 30° rating, and the Hyperion much colder. We, thus, consider the Merlin to be the top bag in warmth-to-weight ratio and have trouble attributing this outstanding performance to something other than sorcery.
Our only significant complaint with this bag is its comfort. Don't get us wrong, the fabric is soft, and the incredible loft of its ultra-premium down creates an extremely cozy cocoon. Rather, our comfort complaint is due to its narrow fit.
With 58 inches of shoulder girth, the Merlin is one of the narrowest bags we tested. This is also a full six inches less girth than the Western Mountaineering MegaLite. Whereas most of our testers found that bag to be extremely comfortable, several of our larger or side sleeping reviewers complained that the Merlin felt constrictive. This probably isn't a problem for shorter trips, when the benefits of less weight can overshadow the drawbacks in comfort. However, for longer trips, or over the full lifetime of a bag, the review team felt that the average user would likely prefer the MegaLite.
The comfort difference between a narrow bag like the Feathered Friends Merlin (orange) and a wide bag, like the Western Mountaineering MegaLite (blue) can be substantial.
A smaller complaint about the Merlin's comfort related to the nosiness of its Pertex Endurance shell fabric. When manipulated, this fabric creates a distinct crinkling sound. Although it's only subtly louder than most other bags, some lighter sleepers felt the difference was enough to disturb their sleep.
Like its low weight would suggest, this bag packs down pretty small. With the help of an aftermarket compression sack, it achieved an impressive 7.3 liters in compressed volume. This is nearly the same as the Western Mountaineering MegaLite, but surprisingly larger than the heavier Nemo Kyan 35 and REI Co-op Igneo 25.
For its larger volume, however, the Merlin provides substantially more warmth. To fully enjoy its small packed size you will need to get a third-party compression sack. This will set you back an extra $20 but improves its packed size over the simple stuff sack that it comes with by roughly 20%.
The Merlin is pretty bulky packed inside the yellow stuff sack that it comes with. A good compression sack, however, can compress it considerably smaller.
Both of the Feather Friends bags we tested feature some of the longest zippers in the backpacking sleeping review. These allow the Merlin to vent excess heat as well as any other bag we tried, expanding the range of temperatures it can comfortably be used in. When opened fully, the long zipper also effectively turns the bag into a quilt for sharing on a chilly morning or between climbing partners during a "light and fast" bivouac.
Its one versatility drawback is its down insulation. Like all down products, this down will lose its ability to insulate if it gets wet. Thus, this bag is not well-suited for particularly wet climates or activities.
Continuous horizontal baffles allow you to move feathers to the top or underside of a bag to adjust the amount of insulation.
Features and Design
Although it's just a simple mummy bag, we like this bag's features and design. The zipper, as we mentioned above, is super long for venting excess heat.
It also incorporates an effective anti-snag zipper slide. The fabric adjacent to this zipper is stiffened by an internal strip of flexible plastic that further reduces the likelihood that fabric will get caught in the zipper's teeth.
The Feathered Friends bags that we tried feature a Y-shaped zipper slide and an internal strip of flexible plastic to prevent the zipper from snagging.
We also prefer the hood design on this and other Feathered Friends bags compared to their Western Mountaineering rivals. Placing the hood's drawstring slightly back from the hood opening creates a cozy tube of insulation around the face that our testers found to be warmer and more comfortable.
The snap that seals the Merlin may be simple but it's easy to snap and effective at keeping it closed.
This bag's balance of awesome warmth and exceptionally low weight leave it well suited for situations where the ounces count, but you don't want to shiver yourself to sleep. We imagine ideal activities might be mountaineering, alpine rock climbing, or longer backpacking trips when you can't avoid occasional colder nights. These best applications, however, only apply to travelers that aren't bothered by its narrow dimensions.
The Merlin is our favorite backpacking sleeping bag for when we want to go light. Pair it with a backpacking tarp to really trim the weight of your overnight kit.
Although the Merlin certainly isn't cheap, it does cost a little less than similarly performing bags. If you're going to spend several hundred dollars on an ultra-premium sleeping bag, however, this $50 or so savings probably isn't worth factoring into your decision. Instead, simply choose the ultra-premium bag that's best suited for your sleeping style and expected applications. Whether that's the Merlin or one of its competitors, you will receive an expensive bag that still provides an exceptional value because it can last for over a decade.
The Feathered Friend Merlin's greatest strength is its incredible warmth-to-weight ratio. We also think the long, anti-snag, zipper performs better than any other, giving this bag an edge in convenience and versatility. However, the narrow dimensions that contribute to this bag's low weight come with drawbacks for its comfort. Larger and side sleeping testers found these dimensions to be uncomfortably constrictive. The Merlin is thus our Top Pick for users interested in "fast and light" missions where sacrificing some comfort for lower weight is often worth it. The average backpacker, however, may prefer the slightly heavier but more comfortable Western Mountaineering MegaLite.