I have their older jacket, pants, beanie, and gloves. On one late season cow elk hunt I used them down to -12 F (not counting 35+ mph winds) with a base layer underneath. Here is what I found:
* They are very warm.
* They block the wind.
* They are well suited for stationary hunting (ex: sitting in a blind).
* They are not suited for elevated/sustained amounts of physical activity; you will overheat.
* The temperatures need to be cold all day.
* Gloves could be better.
* Will be the most refreshing leak you ever take when the heat escapes.
* Do not pass gas while wearing the pants/bibs. It will "stew".
I decided to keep the setup for potential future hunts where it'd be well suited; I do bring the jacket out a few times a year when waterfowl hunting if it is really cold.