A very wonderful warm jacket. Feels very light to wear, almost can't even tell it is there when moving. Stretches nicely. Breathes very well so it is easy to stay comfortable in changing environments/activity levels.
They made at least two revisions, one that had an adjustable hood (in the upper back of the head) and one without. The one without can get in the way if I turn my head far to the side, but isn't a deal breaker, and often the hood wasn't needed by me but very nice when it is there. The one with the adjustment makes it easy to snug it up so it almost feels like I am wearing a beanie that stays completely out of the way while also keeping my neck warmer. That one also has some flaps over the hand warming pockets which, so far, do not seem very helpful and more often feel like they are poking out rather than laying nice and flat.
Because of how light, flexible, breathable, and stretchy it is, it is easy to wear something more durable over it and use it a warming layer comfortably. It is also possible to put something underneath as well, and it doesn't feel oversized in order to accomplish that. It feels about as warm as any of their level 3 jackets.
A very flexible jacket. Having just this available combined with a more durable level 5, without its own insulating layer, would work in a very wide variety of environments. Wear just the other level 5 if it is warmer, the alpha if it is cooler, both if it is even colder (or perhaps raining hard). The Stretch Alpha is more durable, flexible, and water repellent than a lot of level 3 options filling in more situations.
I really hope that they do not get rid of this jacket. Replace it with a refinement of it, if anything.
Highly recommend it over their attempt at an imported one, the Aptus Hybrid Softshell L5 Jacket. That one is *much* heavier, I am confused where all the weight comes from, I don't trust the outer fabric as much, and the sleeves and cuffs are too tight (especially if you have a watch) even if you get a size larger than you need (which then results in the body being too baggy).