I went to REI today to check out the Arc'teryx Beta SL. I went to try it on to evaluate a potential pickup of the Alpha SL. Essentially, the two jackets should be the same with a few exceptions -
But I left with a funny taste in my mouth. Essentially, it was a case of not what I needed, but what I didn't need. I took contention with a few things:
First, the zippers are your standard waterproof zippers. They look the teeth have a layer of rubber on the exterior. But it is difficult to zip up the zippers, and it appeared that the waterproof protection contributed to the significant difficulty.
Second, the hood. I had two issues - the draw cords could not be used with one hand. Also, the hood was meant for a helmet. I had to pull the cords significantly and crank down the rear adjustment to fit the hood as tight as I like it (a la my Precip). The hood however, was otherwise great. There was plenty of side (cheek) protection, and the brim was extremely stiff.
As for its features, it had two good-size pockets, no pit zips (which may or may not be necessary) and a huge hood.
As for these problems, I anticipate the Alpha SL having similar problems with the zippers, and the hood would be huge (it is designed as a ultralight alpine jacket). However, I could operate the hood one-handed. I tried this on a Theta AR, and it was tough to pull, but doable.
I'm slightly disappointed with what otherwise is an amazing shell.