The Mammut Aenergy is a trim, lightly insulated aerobic softshell with front-side wind-resistant facing.

Weather Protection 
A delightfully cuddly and warm fleecy lining combined with excellent frontal wind-resistance allowed me to face freezing winds with confidence – so long as I was meeting them head-on. Once the precip started, however, I was forced to layer up or retreat.

Breathability
The Mammut Aenergy’s tendency to absorb and hold wetness made it feel progressively less breathable as we turned up the internal temperature. It performed better in temps below 35F, though I still felt the need to unzip if I was pushing hard.

Mobility/Comfort
With plenty of stretch, great cuffs, flat seams, super-soft lining, comfort was the Aenergy’s strongest strength. I did notice the forearm seams a bit more often than I would have liked while wearing short-sleeved baselayers.

Weight
While the Aenergy was the heaviest aerobic softy I tested this season, it was also the warmest.

Attention to Detail
Although Mammut seemed to get the broad strokes right with this jacket, the details were disappointing. I felt that the Aenergy’s useless cord-locks at the hem and, especially, the apparent lack of water-repellant treatment were big issues that significantly hurt its performance.

Value
Had this jacket performed more like a softshell and less like a fleece, its list price may have seemed more reasonable.