First, you should probably try on a jacket before you buy it. Patagonia jacket squeeze my shoulders and Arc'teryx jackets seem to be constructed specifically for me. However, reading the reviews of other things manufactured by the company makes one think that perhaps they've just hit on the ideal measurements. That being said, this is one of the best pieces of outdoor (or an other) gear that own, and I have a serious addiction to gear. I have owned the jacket for 5+ years and taken it pretty much everywhere I go. It's been dragged over rocks, collided with trees, and withstood the vagaries of airport baggage handling. Somewhere along the way a few stitches came out, and Arc'teryx fixed them for free and with a week turn around. It is lightweight and very breathable, making it ideal for wandering around in. As opposed to another poster, I do not think that the jacket is waterproof. It will become soaked if you're in the rain, but it will also dry out pretty quickly once you find some sun. If you need serious warmth, get a down jacket. If you're in the Olympics during the rainy season (350 days of the year, I believe) get a shell. If you're doing anything, this jacket will help get it done.

I wore my Gamma MX 5 of 6 days while in Lech. The weather ranged from a balmy +5C to -14C. The Gamma MX was excellent in all conditions. Here was my layering scheme for the cold days: base layer was my Nike Dri-Fit form fitting shirt open air mesh, mid layer was my Arc'Teryx RHO Top and the GAMMA MX that's it!! Lightweight, wicked breathable with plenty of pocket storage. You also get the "Nod" from those who know all about Arc'Teryx... a good way to hook up with your fellow Canadians and Yanks on their ski trip to Europe. I only wear my Sidewinder SV in really nasty weather now.

The warm weather day in St. Anton you ask? I wore a Patagonia Lightweight Capeline T-shirt, Patagonia R-1 for my mid-layer and the GAMMA MX. Here I discovered how the GAMMA MX breathes. I concur with all the other posters on this jackets breathability. Everyone was sweating BIG TIME except me! Nuf said! BUY THE JACKET!!

I finally got my Gamma MX on the day of Helsinki's first snow storm of the year. The temperature was -5c, though it felt like -10. I went outside waering only a Patagonia R.5 microfleece under my Gamma MX. The verdict: I was slightly cold. Keep in mind that this isn't the proper layering strategy. A couple days later I went out side (Temperature was -5C, but it felt like -12C) wearing a cotton t-shirt and Arcteryx RHO Top under the Gamma MX. The Verdict? I was toasty warm!

The Gamma MX is decepitvely light! My friends couldn't believe that such a jacket could protect someone in a cold and damp environment. Helsinki is right on the Gulf of Finland. I don't have any complaints about the jacket at all!

I will go skiing in Lech, Austria in January. I will post another review then about the Gamma MX on the slopes... I know that's what all of you want to know about how it performs. As an owner of many Arc'Teryx products, all I can say is that they are simply the best. The price should be the last thing you think about!

Very nice jacket, well made. Jacket is light, unbinding and weather resistant. Fits very well and looks good too. Should last for a long time. This site delivered fast and professional in the transaction.

On my second one. These fit like a glove and offer great range of motion.

The big caveat: as with all Arc'Teryx products, this is a really expensive garment, but it's worth it...

First of all, they claim the jacket is water-resistant, when in reality it's somewhere between water-resistant and water-proof. And in my experience, it is closer to water-proof. I skied all day with the temp in the low-to-mid 30s and a steady light-to-medium rain. With only a body-fitting thin insulating top (one I use for road biking in cool weather)under the jacket. Verdict: at the end of the day I was warm and dry. Although, in a hard and sustained rain you might over time feel a little dampness. But after all, if I am going to be in hard rain/storm conditions, I put on their Theta LT and become bombproof.

I also use this jacket to roadbike in cold weather conditions as the range of motion could not be greater. It works for cycling because it fits close and stays out of the way.

You can and will wear this jacket everywhere if you get it. From skiing to mountain biking, from work to church, and from fetching firewood to throwing back Guinnes at the pub.

If it seems I am a true believer, it is because I am. I have purchased a Arc'Teryx backpack, Theta LT jacket, and now the Gamma MX (and will soon be bankrupt if I keep going!). Every new purhase I make from them further convinces me that they have no peer in the industry (although Mountain Hardware's pack and trail pants are awesome)

Hope my mania helps undecideds!

Twice a week I ride horses. Last winter I used fleece as outer layer, collecting all the dust and horsehair. Goretex was scrapped and then I found GammaMX. Used it for 3 months now. The fit is tight which is excellent for holding the reins. Easy to clean of the saliva from the horses mouth :-)Great product!!

This is a wonderful jacket. It’s technically superior. I have been using it for over a few months now—on the slopes and off. I wish I could afford a few more, because I am wear it almost every day. And the only aspect that rivals this jacket in terms of quality is this site’s service. You guys are 100%.

I hiked the last weekend of January in the Ardennen, a national park in Belgium (Europe). I used my new gear and it was great to wear my new Gamma MX Jacket (Arc'Teryx). Snow and rain didn't have any effect on me, it kept me warm and dry! Perfect gear when you are in motion, it fits like a second skin!

Great jacket, lightweight, lives up to everything it is described to be. BackcountryStore.com great for orders outside of Utah, very quick with shipment. One of my better experiences with online shopping.

I just recieved my Gamma MX and I was impressed right from the start. Fits like second skin but you have a wide range of motion. Granted it is summer when I bought it but I wore it while I did a myriad of chores outside to see how breathable it was. I was suprised when I did not overheat (don't necessarily recommend doing that though). I can not wait for winter so I can give the jacket it's true test on the craggy face of any mountain on my snowboard. So what if it is pricey, it is worth it, take it from a man who watches his every penny. You will not regret this buy!!!!!

This jacket is outstanding. It has the perfect combination of protection & wearability for almost any conditions. The Gamma will fit right into our rescue operations in Iceland!

I bought the hoody, and think it's definitely worth the extra money. Pull the hood up, and it keeps the snow and wind from your neck. It's helmet compatible, and has two elastics to cinch down if you're not wearing one - like around the town. Works beautifully. No VELCRO(r) to get stuck on other clothing. Awesome. Pockets open to vents to give you pseudo-pit zips. The inner lining is cozy, and the jacket is quiet and minimalist. I wear it to commute by road bike, ski, and hike. In 0-20 degree weather, I have a heavy midlayer + base. In 20-30, a thin fleece. In 30+, a polypro does perfectly fine. Always comfortable. If I had to complain, it is that I wear it so much that it's gotten dirty - maybe it picks up dirt more than a hard shell?

The Gamma MX is a nice jacket, but I wished that I had bought something different. I'm a tall man and the coat is styled to be very short-waisted. There were some stitching flaws near the cuffs and there was a seam starting to separate that I'll need to fix soon. Next time I'll look at the Spyder line a little closer. The Arc'teryx line is not a very good value, in my opinion.

This is a great technical jacket that happens to be tres functional in the city. It doesn't fit as close as the Gamma SV, and I'm able to wear a heavy fleece underneath; and that's a great combo for cold weather. It's close to being totally H2Oproof, blocks wind, and has repelled baby puke (don't ask). It's really good for climbing as well as holding onto subway handrails. As such, the sleeves are cut longer, and the wrist closures are pretty tight (you won't be rolling up the sleeves). Plus, it's a smart-looking jacket.

Difference between the SV and the MX? The MX is warmer, but the SV repels H20 better. Also, the men's version has blue-greyish colored pockets; the all black version is for women.

This is a great, close fitting jacket for mountaineering and other backcountry activities. It stretches with one's movements and has proven to be more durable than I had anticipated. It fits much better under shells than any other "fleece" that I have used. This is a winner!

Just spent a rainy weekend in Basalt, CO and the Gamma MX was ideal. From 35-50F, rain and a breeze—it was all I needed. This will be my all-around jacket for quite a few years to come.

I debated between the Mountain Hardwear jacket and this one before purchasing. I made the right choice! The Arc’teryx products are put together so well that you don't have to worry about them when you need them most. These guys think of everything in their clothing. This is a great jacket for mild temperatures or for layering purposes. I'd recommend it to anyone to depends on good gear for their lives.

I recently used this jacket on a climbing trip I took to Indian Creek outside of Moab. It performed above and beyond the call of duty. The temperature was at a level where you are cold when sitting around but hot when active. The Gamma MX provided the perfect insulation for time at belay and breathes very well for when climbing. I noticed that is very abrasion resistant as heavy contact with gritty sandstone had no effect. It also provided excellent water resistance for the surprise desert rainstorm. Excellent jacket.

I have been a big fan of the Marmot Dri Climb Windshirt until I got my Arcteryx Gamma MX jacket. The Gamma offers all the features of the windshirt but it is very water repellent. I spent 45 minutes wallowing in rotten snow on a 45-degree slope. When I finally got to the top I was surprised to discover I was mostly dry. The snow was up to my neck but the jacket never got wet. I was sweating like a hog but within five minutes I was dry. This is an amazing garment.