Value
The Rab Atmos is very comparable to the Mountain Hardwear Super Light Plasmic in price and performance. But we found this to be slightly more breathable. Very good value for an excellent jacket.

Weathershedding
The three layer laminate blocked rain like we expect a hard shell to do. An extra flap of fabric backs up the water resistant YKK Aqua Guard front zip. The two hand pockets are more suspect, but are tucked under the arms; we didn’t notice any leaks until we sprayed the pockets directly with a garden hose. The hood fits snug and a brim kept the rain off our faces.

Breathability
This was our first real test with Pertex Sheild+, a three layer membrane designed to compete with Gore Active, Polartec NeoShell and the like. We were impressed. We like to take all hard shells on 45 F mountain bike rides, a torture test for breathability. The Atmos was a stellar performer. On the longest and steepest uphill, where we’re usually soaking in sweat with a hard shell, we just had the zip half open. We always think pit zips are worthwhile, but we got by without them. A button near the collar makes it possible to open the whole zipper and still maintain rain protection—handy in really warm and wet environs.

Function
Despite its minimalist focus there are still plenty of nice features here. Velcro on the wrists makes adjustment easy. Two big hand pockets sit high enough to be out of the way of hip-belts, but low enough to comfortably use for warming our hands. Three-way adjustment on the hood snugs it down like a beanie, so it was never in our peripheral vision. And a clip stores the hood against the collar where it doesn’t bounce around, perfect for riding or running in drier conditions. It has all the features we like in a jacket, but nothing extraneous.

Durability
No issues to date, three months into testing. But it is a lightweight material, so expect it to show hard wear.

Carryability
Packs down to the size of a grapefruit or large orange, ideal for stashing in a pack in fine weather and pulling out when it gets windy or wet. It only weighs 11 ounces, not quite superlight, but definitely on the lightweight side.