Good, but excellent alternatives exist...
I had to purchased these at the last minute prior to a Utah BC trip to replace a lost pair of Obermeyer pants. These ARE really nice pants, but other more functional, alternatives do exist for a lot less money. Had my local shops had the North Face Summit Series Mountain Pant available in my size, I would have gone with that. They were available for $210 locally (compared to $399 for the Theta SK... cheaper here on backcountry.com, but I couldn't wait). The zipper technology is the same, both are Goretex XCR and the North Face adds a thigh pocket that I have found pretty useful on other pants. The Theta's do have a really nice articulated pant leg that conforms very nicely to the bend in your knees when skiing. My recommendation is to try them both and see if you can justify the added cost of the Arc'Teryx.