Here's the deal: Perfectly realized, a soft-shell garment is supposed to keep you pretty dry, pretty warm, and pretty sweat-free in as wide a range of conditions as possible. But the category is breaking down along two lines. On the one hand are garments using Schoeller's Dryskin fabrics. Among them: Cloudveil, with its Icefloe Jacket ($295), and L.L. Bean, in its Schoeller Guide Pants ($125). These are best thought of as a lightweight shells, very breathable and windproof, highly water resistant, and comfortable across a wide temperature range.
Taking a slightly different tack is Polartec and its Powershield fabric, which is a light fleece layer bonded to a tough, water-resistant outer layer. It's definitely warmer than the Schoeller stuff, but that means it's not quite as comfortable when it warms up. I have a Cannondale jacket made with Powershield that I use for bicycling. Anywhere from 25 to 40 degrees, I put that on over a light synthetic T-shirt and I am good to go, uphill or downhill, even in light rain. But the stuff isn't quite as water-resistant as Dryskin, and takes longer to dry once it wets out.
I could be persuaded that either approach would work well for skiing. The Dryskin would make a great light shell that may require some layering, while the Powershield would make a terrific stand-alone jacket worn over a very light wicking layer. Not too many companies are using it yet, but it's starting to catch on in addition to the Cannondale Thermal ($185), Arc'Teryx makes a piece called the Gamma SV ($240) that uses Powershield. I'd like to see some ski companies step up and do something with it, too.