RE: Feathers of Vanes?
It depends. A well tuned bow/arrow setup is what makes an arrow fly well. In less than perfect shots feathers will do a better job of stabilizing an arrow quicker, especially with broadheads on it. There is an initialspeed gain with feathers, usually about 5fps, as they are much lighter than vanes. They do tend to shed speed quicker due to the increased drag, but there won't be noticable difference till the arrow reaches about 50 yards. After that the vanes will retain a greater percentage of the initial velocity.
Feathers should be treated for water prior to hunting as they will lay down after getting soaked. I don't find it much of an issue with a well tuned setup, as I actually tune mine to be able to shoot a bare shaft with broadheads. Fletching almost isn't needed inside 30 yards. There are several products that can be used to treat feathers to shed water.
All told, I like the additional confidence I get from knowing I have the best guidance system on my arrows for those less-than-perfect situations.