Even though I already have a Patagonia micro-puff, I picked up this vest to match my new ski shell. (Before you judge - I got it on sale for 65 bucks!) Anyway, after using it about a dozen times, I can honestly say I wish I'd never bought the micro-puff. This vest is great - super light, extremely warm for it's thickness, and very functional for use under a shell. Here are the details -

I'm 5'10"/180, and I bought the medium - I wanted a good fit without too much bagginess (is that a word?) to use for layering. I'm not overweight, but I do have somewhat narrow shoulders and big hips (42" chest, 33" waist) with a medium torso, so plan accordingly. I am very happy with the fit - it works comfortably over a long-sleeved base layer and a size L 100 weight fleece, although for anything over 20 degrees, I've found just wearing it over a base layer and under my (uninsulated) shell is plenty of warmth. If you think you'll feel the need for more/thicker layers underneath, I'd suggest one size up just to be safe. The only issue I had with the cut was, even in a medium, there's excess space through the mid-section. I guess it's insurance against an over-sized belly, but for someone who has a fit build, the vest on its own will look a little weird when it's zipped up.

The vest zips up to a very high collar; I found that to be perfect for skiing - no need for a neck warmer or any of that crap. Also, the neck is perfectly sized - not too loose to let a bunch of air/snow/beer down it, but not so snug that it won't fit comfortably over a zip-up baselayer and zip-up fleece.

The fabric is very slick - it moves easily under a shell, even up in the neck area. I can't attest to it's durability, but it did shrug off my girlfriend's spilled cocktail après-ski! (OK, fine, the foul was on me!)

The vest is long! It easily covers the first 3-4 inches of my ski pants, maybe more. The snow skirt on my shell hits well above the bottom of the vest, so keep that in mind. I found that cinching the bottom of the vest worked pretty well to keep out snow below the skirt. Heed my warning - leave it loose and the vest becomes a chimney which will easily distribute wonderful frozen wetness all the way up to your neck!

This next item may seem a little strange, but the arm-holes on the vest seem high. I suppose that's good from an insulation standpoint, but I've never had a product that rode up into my armpits like this. They are elastic, but there's not a huge amount of stretch there. For reference - I have a Mountain Hardwear Sub-zero vest with well-fitted elastic arm-holes, and this vest (both are mediums) seems tighter in that regard.

The vest has excellent functional design - big pulls on the zippers can easily be manipulated by half-frozen, gloved hands, and the exterior Napoleon pocket is well placed, easy to open, and adequately sized. (Why anyone would make a vest with an interior chest pocket - Patagonia - is beyond me! Hello - layer!)

Finally, I love the color! If you're a slave to fashion, or just AR like me, the Asphalt Grey color matches the lining of the Arc'teryx Stingray perfectly - right down to the subtle grid pattern! Even if you're lucky enough to not suffer from OCD tendencies, my guess is that you'll still like the looks of this product.

In conclusion - great product! Way warmer than it's thickness would suggest, and, despite some idiosyncrasies, an overall excellent vest. Highly recommend, especially if you can get it on sale!

I bought this vest a couple years ago expecting to only wear it sparingly under a shell during very cold winter camping and skiing trips. I've subsequently found it to be my one of my favorites, and I've worn it during a variety of activities for which I never thought it would be applicable. I would highly recommend this product; it's good as an outer layer over a light fleece, under a hunting jacket, under a shell, or even over your dress shirt for commuting when you just can't stand looking like another robot in a felt coat! I'm not sure if any changes have been made, but mine has a hem drawstring as well as another one about 4 inches up from the hem across the lower back, so it can be cinched up to fit like a glove. The only other vest I have for comparison is a Patagonia micro-puff, and this one actually fits me much better. (I'm a Med in almost everything) The quality is outstanding as well; I would argue the construction is as good as or even better than my North Face Nuptse full-sleeved jacket, (circa 1998?) and I actually prefer the outside fabric on this vest to that of the Nuptse. It blew feathers for about a month, but that's all done now; also, the collar must be overstuffed, because I almost completely saturated the back of it with hydraulic oil (other than intended purpose) and it still seems to have a pretty decent loft. Finally, a quick word on aesthetics; I know earth colors are all the thing now, but I got this vest in kind of a carbon color with black and it is sick! Also, the logos are a bit more subdued - just the MH nut embroidered on the front chest and again on the center back just below the collar. I hope they go back to that so you don't look like a sponsored athlete. In conclusion: buy this vest! If you're even remotely in a cold climate (MN here) you'll find an excuse to wear it 8 months out of the year!