I don't know about some of the newer "shredded" vanes told to act like feathers, but generally vanes are heavier than feathers, and so a feather will leave the bow a little bit faster... so I'm told anyays.... I've not used a vane in years.
Feathers will collapse when they strike something, like the riser without unduly influencing arrow flight... meaning that shooting off the shelf with them is generally less of a problem, whereby vanes don't collapse and where there is an action, there is an equal and opposite reaction and that is usually not a desireable aspect of vanes off the shelf, henceforth all the rage of fallaway, flip away, or other get out of the way rests.
I don't shoot vanes anymore, but I do shoot feathers. I don't shoot off a rest, just off the shelf. I try not to shoot in the rain, but here in Hawaii it is generally inescapable but I've found a foolproof way to solve the rain issue with clear-wrap and a rubber band
Pulling the clingwrap pulls the rubber band off with it without harm to the feathers..
Clingwrap can be spray painted or tucked into a camo bag and then pulled over the feathers if you want a true camo for non-rain days with chance of rain... personally nowadays, if it is raining I'm in front of the fireplace...
I carry trash bags with me always and i have rubber bands and tiewraps in my pack, so in a pinch, I can always wrap one or two feathers if I'm caught.
I've soaked some feathers (well sprayed) in water proofing I used on my boots and I've used mink oil on others but haven't had the guts to go hunting with them "naked" to check it out. They work on a dipped arrow and shot, but that is not a cumulative effect from rain all day and that second shot after being dipped again hasn't been tried. It slows the arrow down (and why not, you're adding weight with spray) though... not enough to stay home.
Feathers, in my opinion are a twofold benefit.
One they are much more durable than vanes to lava rock excursions.... but I'm one of the rare ones chasing errant arrows I'm sure.... and I rove constantly while hunting, and rubber blunts sometimes skip when you can't see what you're actually shooting at at 50 or 60 yards... (yeah I know... I only shoot at 20 so why 50 or 60?... weren't you ever a kid?)
Feathers work well even if one is missing or really damaged... much better than vanes have for me. For me there is no reason to ever use a vane.
This half hour was brought to you by someone looking for an excuse to delay going to work this morning...
Much Aloha...