I was skeptical from the beginning about Polartec Alpha. The very idea of making a shelled insulation garment more breathable seemed questionable at best, as it seemed rather likely that light fleece plus a windshell would be a better solution in every respect. Fleece and a shell is probably a better option for most backpackers most of the time, but Alpha has merit and contrary to what I first thought, the Strata hoody has a place in my closet.
The Strata is vintage Rab, and has the same fit and feature set as the standard setting Xenon. Two zippered handwarmer pockets, zippered left chest pocket (which is huge and inverts as a stuffsack, drawcord hem, sculpted lycra-bond hood. A welcome change is a #5 main zip, as opposed to the #3 used on the Xenon (which blew out after two years on mine). An unwelcome change is the goofy cuffs, which have elastic on the inside half only. It's effective, but causes the inside sleeve near the wrist to puff out and get in the way. Fit is excellent; roomy but not baggy, very long sleeves, body long enough to stay sealed but short enough to not stick out under a raincoat. The Microlight shell is different from the normal versions of that Pertex fabric; it has a matte finish and is a bit softer and quieter than the stuff found in (for example) the Montane Litespeed. DWR is what you'd expect from a leading brand.
The sell on Alpha is that it breaths much better than traditional synthetic insulations like Primaloft and Apex. This is facilitated on the inside of the jacket by making significant portions of the liner out of mesh, and by the more air-permeable version of Microlight used for the shell. This works: the Strata moves moisture a lot faster than something like the Xenon. It's also not nearly as warm, something especially noteable given the increased weight (~16 ounces for the Strata, around 4 more than the same sized Xenon).
If you throw the Strata on for pure warmth, you'll be disappointed, especially under windy conditions. A bunch of testing here over the years has revealed that the more air impermeable fabrics (Pertex Quantum et al) add significant warmth to jackets and sleeping bags, and comparing the Strata to the Xenon or a similar traditional synthetic jacket proves this.
But warmth in the backcountry isn't so simple. A classic winter layering problem is sweating on the uphill (even when properly layering down and venting), then getting chilled on the flats and downhills which follow. Putting on a light synthetic coat like the Xenon sorta solves this problem, except that fabrics like Pertex Quantum are almost as good at keeping moisture in as they are at keeping wind out. Use the Xenon in this manner for a few laps backcountry skiing, or a few transitions on a hilly route snowshoing or cross country skiing, and you'll likely experience a steady accumulation of dampness in your base layers, and in the synthetic jacket. This usually works out ok on a day trip, when a warm car awaits or you can carry extra clothes, but can present a serious problem on multiday trips.
A piece like the Strata goes a long way towards solving this problem. It provides enough warm and wind blocking to keep core temp steady, and vents much better than anything in its class. Why is it better than putting a thicker fleece under your windshell? Simplicity. Stripping down to relayer is slow and, on a windscoured ridge, unpleasant.
I foresee the Strata being a part of a two puffy system for me this winter; with the Alpha piece being the moving puffy and secondary insulation, with a traditional synthetic jacket going over the Strata in camp. It won't be the lightest system, but it might be the most efficient over many days.
The Strata is also a nice mid/outer layer combo for slower activities in cold weather, or (I assume) higher output stuff in real cold. I wore the Strata over a capilene 4 shirt the other weekend mountain hunting on a day which barely got above 0 F. Having a two layer system which vented well enough when hiking up steep hills in the snow, and kept me warm enough while standing around glassing, let me focus on other things, stay comfy all day, and helped bag a nice deer that afternoon.
Discuss.
