It has the perfect combination of fit, features and aesthetics that checks all my boxes.
The fit block is the best for my body, I might be wrong but I believe it's the kimono gusset (kg) which keeps the sleeves pretty tight but allows full range of motion at the shoulders. It then keeps a straight profile in the body which pairs very well with p15/23ts which is my favorite style of pants.
The feature set has the double pocket on the chest obviously but then has gravity pockets (scan card) and zippered detach entry hand pockets which are simple but well done. The quick roll up hood is my favorite as it keeps it out of the way but easily deployable, much better then the snap off hoods. I don't use interops but it's available as a nice vent for when I wear it in warmer weather.
The color blocking is very dramatic, the shade of green/brown/olive fits very well into my wardrobe.
I had sort of grown out of the jacket recently due to weight lifting, and was having particular issues getting the jacket closed across my chest comfortably. Chris (_coded) was kind enough to work up an expansion panel similar to the one found on the j43a; it's added the additional benefit of improved headphone routing, better fit and flair at the waist and lets me layer a sweater under it comfortably again, as well as making interops a more viable option.
Edit: holy shit didn't mean to type so much