COMFORT
The Nathan VaporCloud 11 is very comfortable due to its body-wrapping feel and fast wicking materials. The back panel has a blown nylon later which promotes air circulation between the body and the pack. Also adding to comfort, the pack places its weight at the middle of the back to relieve some weight from the shoulders. 

STABILITY IN MOTION
This pack shines with regard to stability by placing several elasticized straps across the sides, chest, and hips. The design feels more like a vest than a backpack, which keeps everything in concert with body movements. 

WEIGHT
The pack weighs 1lb 3oz which is just above average for its class. There is some extra weight in features such as whistle, reservoir insulation, and extra strapping for trekking poles. 

QUALITY OF CONSTRUCTION
Construction of the Nathan VaporCloud 11 is good with strong seams and robust straps. The mesh paneling is very light and prone to tearing, which is expected from a lightweight race vest. 

MULTI-SPORT VERSATILITY
The Nathan VaporCloud 11 is not a great choice for multi-sport use due to low carrying capacity and how tight the pack fits to the body. For activities other than running, comfort would be marginally low compared to other packs in its class.