I was originally considering the Patagonia Puff Jacket or Pullover as an insulating mid-layer under the trim-fitting Mountain Hardwear softshell that I just bought. But, the Patagonia pieces are cut large to layer over other garments and are relatively heavy (more than twice the weight of this piece). I just returned from a week of climbing long trad routes in the canyons of the Red Rocks during an extreme cold spell during which daytime high temps ranged from the 30s at the beginning of the week to the 40s later in the week. I had the Thermawrap jacket and pants with me during the entire time. They pack small enough to fit into my minimalist Platypus hydration pack, and provided a very impressive amount of warmth, keeping me comfortable after the sun set and the wind picked up, bringing temps below freezing. The jacket breathes well also, and I stayed dry even when working out hard on the approaches. The jacket looks good around town as well. Overall, it's just a great piece of gear.

I am an ultra lighter who finds function much more fashionable than fashion itself... Very light jacket. It might not have all the bells and whistles that other jackets in it's category would (i.e puff jacket or compressor) although it less than half the weight and properly layered it gives you much more flexibility which provides higher overall function, warmth and options when overheating. The only thing to be aware of is a VERY "techy" fit (it runs small). Definitely brag to my friends about this gear, even if they are skeptical...

The Montbell UL is a great jacket. As usual I am impressed with Montbell's quality and attention to detail. After sizing issues for a couple seasons this update nailed the fit and added a new front zip and handwarmer pockets. At 6ft and 180lbs I fit the large perfectly. Slightly higher cut is ideal for climbing harnesses, but does not ride up even on my long torso.

This jacket is a mere 9 oz., perfect for the ultralight junkie and the super warm Exceloft seems thin but is warm for the weight. My UL could take the place of a heavier fleece and when used in conjunction with a light fleece felt as warm a heavier down jacket. The 15oz. shell may seem delicate but it is tougher than I thought and has held up well while hiking in thickets and brush. No snags.

Stylish enough for kicking it around town and ideal for Spring to Fall excursions or an extra winter layer. I could live in my UL 24/7....it's that comfortable.

This is my first Mont Bell product and I can say that I am a huge fan!
Great quality workmanship/materials. Super light weight and packs small (smaller than a 1L nalgene bottle). Great warmth for its weight (too warm to wear indoors). I generally wear a medium (5'8" 150lbs) and find this jacket to be on the smaller side, which for its intended use (layering under a shell) will work just fine. I would suggest sizing up if it is going to be used for casual wear. On one other note, the shell material is very shiny... which is a small trade off for a otherwise great piece of gear.

I thru-hiked the Pacific Crest Trail in '06 with this jacket to replace the mid-weight fleece I used to hike with. Overall, it was great, but by the end of the hike after so many months of compressing it, the insulation had lost most of its loft. Such is the nature of synthetic insulation, though, and I'm sure any of the competitors jackets would have done the same. Bottom line: great jacket, and I'd buy another one at the drop of a hat.

this coat is not too thick but really warm. it is good for everyday and especially on those brisk days.

When this jacket arrived I was surprised by the thinness of the jacket. It is very thin. I did not think there was any way that it would keep me warm. I tested the jacket out on a chilly (25F - 30F) and relatively windy night while walking my dog. With the wind chill, probably more like 15 - 20 degrees. Jacket did a great job of keeping me warm, and is breathable as well. Also, packs down nicely in included stuff sack down to less than Nalgene size. Glad I purchased the jacket.

This is a great layering piece for fast and light mountain travel. I couldn't believe it was almost half the weight of my Mt. Hardwear Compressor, but it seems to be true - they do it by eliminating shock cord, zippers and toggles, among other things, but it weighs near nothing and packs tiny. Not super warm, but perfect for the Pacific Northwest or as a second insulating coat. Note: the fit is also pretty minimalist, especially around the shoulders.

Great jacket. Very light, super packable and very warm for it’s weight and bulk. Perfect layering piece or just worn on it’s own. I use this with/under a Patagonia guide jacket and with the two it’s the best layering system I’ve ever owned. This is the first MontBell product I have purchased but will definitely not be my last.

I had to return it because it was too snug and felt restrictive. With about a 40 chest, 5'10" 165 lb., the medium was too small across the back and elbows.
Great quality, a little on the crinkly side, as are most of these type fabrics, but very impressive for the money. Didn't want to send it back; tried it on again and again. Probably a Large would be nice.
Looking at the Bozeman Mountain Works Cocoon offerings. Could this garment be superior in maintaining loft in the face of pressure from a shell?

Used on the second half of my AT hike last year. Super lightweight and warm. Great for ultralight backpacking.

Who needs down?! This new jacket the single most worn garment I own. It's so lite, yet so warm! Where I live in CO temps regularly drop below zero. I ride my townie bike year-round & this light jacket keeps me warm, worn over only 2 light layers. I anticipate carrying it in my backpack, stuffed into its' tiny sack. Best clothing purchase I've made in many a yr. My first mont-bell, but not my last. backcountry.com's free shipping sealed the deal!

I recently took this jacket on a trip to Ecuador and it handled trekking and mountaineering beautifully. It was a perfect layering piece under a shell on the bigger hills and was wind resistant enough to stand alone at lower altitudes. It's also very, very light and packs down very small. A fantastic buy.

Great jacket! Stylish enough to be in a Beastie Boys music video and still provides light weight warmth. The hand warming pockets were a pleasant surprise.

This is a great jacket, it's very warm for it's weight. However, I did find that it fits pretty tight. You might want to go one size up when ordering.

This is the first winter i have had a "winter" coat. It wasn't much of a coat as it was this Jacket. Super lightweight to the max. I have also used this on a backpacking trip, and I can say that at 6.7 ounces, this is THE MOST LIGHTWEIGHT JACKET EVER.

A little too thin for me. Doesn't really make sense. Otherwise a great fit, high quality and comfortable.

This jacket, like most everything made by Montbell, is high-quality. Additionally, the size L I ordered fit me very well. Nonetheless, I sent it back as I couldn't see where it would fit in my clothing arsenal. The synthetic insulation is thin (about as thin as synth gets) though I suspect it's warmer than it looks. My thinking is that it's probably not warm enough for me for stationary use (i.e. high mountain camps, winter lunch stops, etc.). However, it's likely too warm for use while on the move as I sensed that it didn't breath very well (had a plasticky feel to it). I'd rather wear a light, breathable fleece vest for this second purpose (like Pata R2).

This may be the answer for some people but it wasn't for me. I may get a Thermawrap Parka (which has a hood and more insulation, yet is still quite light) instead.