The very mention of any fletching besides natural feathers on the arrows used by recurve and longbow archers makes many in the "traditional" community see red and spew profanity. To these purists, any synthetic material is a sacrilege and an offense to the "traditionalness" of their sport. As far as I'm concerned, that's bull.
I absolutely love shooting traditional bows, but I’m more concerned with hunting performance, functionality, and value than I am about nostalgia or some abstract notion of purity.
There are few elements of a traditional archery setup that are as critical as the fletching on arrows. I used to shoot turkey-feather fletchings on my recurve arrows, but since I've switched to shooting vanes, I have no reason to go back. Here are some of the positives of synthetic vanes on traditional shafts:
Probably the biggest reason to make the switch to vanes is that they are much tougher and more weatherproof than feathers. They are basically impervious to rain, and here in Alaska, we get our fair share of inclement weather. Even in dry conditions, feathers tend to get torn up and worn fairly quickly.
Although it's pretty minor in a hunting situation, but typically, vanes are much quieter than feathers. I do like the buzz of freshly fletched feather, but in some situations (mainly, longer shots), that sound could alert wary game.
If you shoot a lot, you will go through a lot of feathers or vanes. Vanes are much cheaper.
The most important thing you have to do to successfully shoot vanes is to ensure your arrows are tuned properly. I tune all my arrows as bare shafts so they fly perfectly with no fletching. This will ensure the vanes do not hit the rest.
The other key to shooting vanes is using an elevated rest. I have used two types of rests that both work very well. I shoot a machined riser and can use a cushion plunger/flipper style rest. They are very tunable and you get great arrow flight. I have used them hunting, but they can be loud and the arrow can fall off if you're not careful. Probably the simplest and most versatile rest is the Bear Weather rest. It's a simple stick-on rubber rest that will work on pretty much any traditional bow. You have to raise your nocking point, but if your arrows are tuned, the vanes will fly true, and it's a great rest for hunting.
If you’re still on the fence about which type of fletching to use, give synthetic vanes a try. I sure don’t miss having to constantly baby my feathers in the field, and I don’t think you will either.