You can drop that myth in the round file.
On a spring trip to Alaska’s Chugach range the weather was unsettled. A combination of wet snow and fog required both waterproofness from outside precipitation, and superb breathability in an overly moist environment to prevent the dreaded sauna effect. It seemed like a perfect torture test for the Shuksan shell, made with eVent™ by R.E.I. Perspiration flowed as expected while I skinned up south Odyssey at Thompson Pass, but I was never drenched in sweat as I normally would have been with Goretex™. What is more, the Shuksan jacket is without pit zips, a vestigial feature with something like Schoeller™ fabric, and I would say the same for eVent™. I won’t claim it vented as well as Schoeller™, but it was close. Nor was it like my undershirt didn’t get wet with sweat, it’s a matter of degree. Wet is noticeably different than drenched and I was the former, not the latter.
The Velcro™ cinch straps around the wrists worked beautifully. Unique to this jacket is a sleeve that is longer on top than the bottom, giving a bit more protection to the back of your hand from wind or rain. A subtle change from the norm, but a noticeable improvement.
The hood comes with a brim for keep precip out of your eyes, with elastic draw cords on either side and around the back to snug it up to your noggin’. These required a bit of fussing to get adjusted right, so I would advise you deal with this at home, not on a ridge in gale force winds. You’ll also be pleasantly surprised at the overall lightweight. If you’re looking for a new shell that improves on the standard waterproof/breathable equation, and is designed with ski mountaineering functionality in mind, you won’t go wrong with REI’s Shuksan shell.