Personally my next bag will be DWR treated down. I believe Marmot sells DriDown bags. Yeah, I love my WM Megalite but I would love it a lot more if its down was DWR treated.
DWR treated down is relatively new and the main advantage is that the treated down absorbs MUCH less moisture and thus retains loft better and does not gain much water weight over many days of use, particularly in damp conditions where drying the bag may not be an option.
Marmot, Patagonia and one other company have proprietary DWR down treatments. Patagucci's method of DWR deposition may be the best one. Time will tell.