My short opinion is this: I think these jackets are terrific. But not everything on your list is an apples-to-apples comparison. The Serendipity ($250) is indeed one of the new-generation “soft-shell” jackets, as is the Salomon STL-551 ($279). The Gamma, however, is essentially a fleece jacket with reinforcements. So a little different creature, one intended more for use UNDER a shell, than as a replacement for a shell.
The Cloudveil and Salomon pieces, though, represent a new trend in clothing — a move toward single layers that do the job of several garments. In the case of these jackets, they’re meant to work in a wide range of temperatures and rainfall conditions. They offer light insulation, breathe beautifully, keep out virtually any gust of wind, and resist all but the heaviest rain showers. In other words, they’ll work just peachy keen in 90 percent of the weather most people face. They also tend to very durable — more so than an expensive Gore-Tex shell — and very light (17 ounces in the case of the Cloudveil).
Both the Cloudveil and Salomon garments use fabric from Schoeller called Dryskin (which has several iterations, including Dryskin Extreme). We talked about this fabric on the site a while back — its chief competitor at the moment is a fabric from Polartec called Windbloc ACT. While similar, the two fabrics seem to have slightly different applications. The Schoeller stuff works best as a true light all-conditions shell, word over long underwear or a light fleece sweater. The PowerShield has a bit more insulation power, so works well for people such as cyclists or cross-country skiers, who are working hard but have intermittent need for more insulation, and who want a single piece to don over, say, a synthetic T-shirt. Cannondale uses Windbloc in a cycling jacket called the Thermal ($175), which I’ve been wearing this winter and have been extremely happy with.
Keep in mind, these jackets do not necessarily replace your current combination of fleece and a waterproof-breathable shell. But they do mean that in many cases you can lighten your pack a little, or hike more comfortably in bad weather. And they take us a step closer to the day when you take one piece of clothing on a hike, and it’s good whether the temperature is 80, or eight.