Comfortable for 3 seasons.
This has got to be one of the few pieces of clothing The North Face has produced in recent times that is actually really excellent. I got it in the Noah Green and think it looks stylish and distinctive without being gaudy and screaming "I'm going mountaineering" which is great when you want to wear it around town as a regular piece of clothing.
I just got back from a very brisk walk around town to run some errands, light rain and around 55F. I wore nothing under it other than a polyester t-shirt and I was comfortable, never felt like I was getting clammy despite having the jacket zipped tight so the only ventilation was through the NeoShell fabric. If I can be comfortable doing some light cardio in 100% humidity on a warmish day it really says something about the capability of the jacket to regulate your environment without needing to resort to pit zips or even open pockets.
The North Face has lost some of it's reputation for producing high quality technical gear in favor of catering to the mall crowd, but I think the Jammu Jacket proves that somebody there still knows what they're doing and cares.
The only negative I can assign this jacket is that it is cut a bit too "american", I'm 5'11 and around 165lbs and find it fits way too loose around the midsection in size M where Arc'teryx for example will fit in a much more natural way for my body type. I suppose this leaves a lot of room for bulking up with down if you want but I would prefer a slimmer cut.