Water resistant...Will I be wet inside...
Water resistant...Will I be wet inside this bag from my own transpiration?
Probably not, unless you are normally soaked inside a sleeping bag. I have used bags covered in everything from Dryloft to Pertex to the 0F version of this bag (the Col) and have never really had a problem. Most of the moisture escapes through the stitching, I would guess. But the water resistance is nice to keep dew and frost from penetrating the majority of the bag.
Down breathes really well, which is one of the reasons it regulates temperatures really well. Unless you are stormed-in in a high altitude bivy for multiple days, it isn't likely that you'll be wet inside your sleeping bag from condensation, respiration, or transpiration.