The Cold Fusion, from an interesting company called Beyond Fleece, is a more typical soft shella basic jacket made with Schoeller's excellent WB-400 fabric. In its basic configuration ($159; www.beyondfleece.com), it's a simple, snug-fitting jacket with a full zip. You can add all sorts of extraspit zips, attached or zip-off hood, arm pockets, and more. And you can customize the size. Of course, all that also jacks up the price to $250 or more when all's said and done.
Choosing between the two is tough, and I'd say they match up on durability. I like the Mixmaster, but the Cold Fusion is probably a better multi-purpose garment. That's because you'll likely still want to throw a full shell made from Gore-Tex or similar material over it as the Himalayan weather worsens or cools. And when you line them up, the Mixmaster is a heavier jacket (26 ounces, compared to the 21-ounce Cold Fusion) and is really meant to be a garment for severe conditions. So the basic Cold Fusion will be better at filling that "layering or alone" niche than the Mixmaster, and saves you a few ounces into the bargain.
Hope you have a good trip!
To see a selection of soft shells compared and rated across a range of temps and activities, read "The Soft-Shell Game" from the February 2003 issue of Outside.