gilipollaswrote a review of Arc'teryx Epsilon LT Softshell Hooded Jacket - Men's on December 16, 2015
Familiarity: I returned this product before using it
Fit: True to size
I'll review both the Gamma MX and the Epsilon LT, which I considered and ordered, and why I kept the Gamma.
I was looking for basically a more fleece-like jacket, with the added benefit of some wind resistance and a smooth face fabric to resist stains and pilling. Use for bike commuting in dry, cold weather, and as a casual piece during the fall/winter.
I initially considered the Gamma MX, Epsilon LT, and the Gamma LT, all of which seem somewhat similar. I eliminated the Gamma LT as it seemed closer to a shell from what I could tell, and lacked a nice inner fleece fabric, which is a must, as I plan to wear it over just a t-shirt and want a nice fabric on my skin. Aesthetically, I didn't like the Arc'teryx logo on the back of the Gamma LT neck either.
So I ordered the Epsilon LT and the Gamma MX. My impressions:
Fit: Fit is about the same, the Epsilon seems just a tad longer and slimmer, while the Gamma MX is a bit boxier it feels. Perhaps this is because the fabric on the Epsilon is quite a bit stiffer. Overall, size M for me, 5' 10, 160lbs, was just about perfect, and consistent with Arcteryx sizing.
Fabric: Both are so good, but different. The Epsilon is classified in some places as a "hard-fleece" which I figured would be more fleece-like than a softshell, assuming the continuum from fleece to shell goes from soft to hard, comfortable to stiff. Not so. The Epsilon is quite a bit more rigid, and doesn't fold and flex like the Gamma MX. It's not bad, it's just not what I wanted. If you're looking for a more handsome jacket to maybe wear business casual, the Epsilon definitely looks better because of that rigidity, and it feels tough as nails, it's really a cool fabric. On the other hand, the Gamma MX is very soft, supple, and lightweight, and I like the way it moves with me much more. It's a lot more comfortable, but feels a little less robust.
Features: Both are great. I'm not a fan of the contrasting color of the bicep pocket on either jacket. Zippers are nice, pockets are large on both. The chest pockets on the Gamma look nice and are roomy, but I don't plan on using them for much. There's a really nice storm-flap on the Gamma, coated in some sort of rubberized plastic, and it's nice. The zipper is nicer on the Gamma. And the SLEEVE CUFFS. This, in the end, was the make or break feature for me. The Epsilon LT cuffs are really annoying. They're too big, so you get the sleeves coming down over your hands all the time. Maybe that's nice if you're wearing a base layer or a shirt with cuffs on it, but the Gamma MX cuffs are perfect size, and keep the sleeves from coming too far down. While wearing the Epsilon, I found myself constantly annoyed with the cuffs in my way. The Gamma cuffs are perfect, I never think about them at all.
I can't comment too much on performance comparisons, because I didn't test the Epsilon before returning. However, the Gamma is great as far as breathability and windproofness. It feels lighter than you'd expect, but in 45 degrees, riding 30mph on a bike, it blocked 90+ % of the wind coming through, and didn't get all clammy. That's much better than any other softshell I've ever used, including Polartec PowerShield and a Marmot ROM. It's expensive, but it works well.
In the end, both jackets are fantastic, and I would expect the Epsilon to perform similarly to the Gamma MX as far as breathability and windproofness. But the cuffs on the Gamma MX are what sealed the deal for me, as petty as that sounds. Maybe that should give some insight as to how similar these jackets feel in form and function.
Maybe they'll fix the cuffs in the future. And hopefully make the arm pocket the same color as the jacket.