I think the reason vanes are so popular is because the vast majority of bowhunters only hunt deer, which means fairly close range shooting. We haunt alot of moose where I live so 35-40 yd shots are often necessary and quite feasible since moose can't jump the string. At these distances feathers are far superior. If you shoot close, use vanes, if you want range in all sorts of weather conditions, use feathers.
For waterproofing I used flytying "gunk", used to treat dry flies. It is painted on the feathers and works great. Now I use a cat quiver by rancho safari (available at Cabelas) which keeps the feathers covered until you are ready to shoot. Always have dry feathers even in driving rain and snow, which is the best time to hunt moose.