We are very impressed by the weight of the Trail Mtn WB, coming in lighter and packing smaller than other windproofs on test by some margin. It is the protection and functionality at that weight that really sold it to us however.
When the air takes a chill, the high collar was snugged right up under the chin to really seal out the draughts, while the light but functional elastic hem and cuffs did the same at the other entrances. The hood isn't quite big enough to pull over our trail helmets, but is otherwise excellent with a small peak and roomy cut. The fabric is soft and quiet in use and, combined with a close fit that discouraged flapping, it is a jacket we could happily forget was on.
When suitably warmed up, we just stuff it into its own chest pocket and tuck it away. An excellent piece of kit for both 'just in case' and every day duties.