to some degree, vanes are lots stiffer, less flexible and less compromising than feathers. really big vanes - 4" to 5" - are more difficult to setup and shoot, imho. you can shoot vanes off a shelf, i've done it with good success. but you better be on yer game and not flub a release.
so why bother with feathers and just shoot vanes exclusively? after all, plastic fletches are totally waterproof.
feathers are far more forgiving than vanes, and they offer far better control over an arrow that's poorly released because they can be lots larger without affecting the release. you can fletch in a really aggressive feather helical and the fletch will still be very flexible - not at all so with plastic or rubber vanes.
but feathers get wet, soggy and totally lose their shape! there are conditioners that will help waterproof processed feathers. when the weather's wet, i'll use arrows fletched with natural turkey or goose feathers - they're naturally bird oil waterproofed.
and lastly - i just GOT to say it! - feather fletchings ARE traditional archery.
processed turkey and canada goose - both held under running water for 5 minutes ... (the goose feathers are free, too
)
ymmv.