Worth every penny and I'm glad I bit the bullet after hesitating for months. I have the mid weight version (love it) and afte a 10 mile hike in 5'F weather I started thinking I wanted a heavier base layer. This is twice the "weight" which actually is just a much denser weave but also possibly softer than the mid weight. Thumb holes are a nice bonus as is the fabric flap over the zipper top to protect your chin when it's freezing.  So impressed with it I treated myself to the leggings as well.

UPDATE 12/2016:  Just got another one of these and they have improved the sleeves by extending them an inch or so.  Makes a big difference as it is more comfortable.  Love it!