One vane weighs more than three feathers of the same length and size. The difference can be substantial. Once past 60 yards, they say vanes are faster than arrows. Frankly, that's at least twice as far as I'll ever take a hunting shot, so that's a moot point. Over typical HUNTING distances, a feather fletched arrow IS faster by a few fps. Whether or not a few fps is that important is your decision to make.
Actually, I've found feathers to be FAR more durable than vanes. I fletched up a half dozen arrows with vanes two weeks ago. The feathers I pulled off before refletching had been on these same shafts for two YEARS. They were still shooting fine, but beginning to look a little ratty. Anyway, half of these freshly vane-fletched arrows already need to be refletched because the vanes have been cut or had holes shot in them from other arrows. Those same shots that ruined these vanes would have just ruffled feather fletches. Feathers get ruffled and you just smooth them back into shape. Vanes get destroyed.
Noise: If you put too much helical on feathers, they will hiss. Even at that, once they've been shot a bit and broken in - lost some of their stiffness, in other words - they're MUCH quieter. On the other hand, vanes can be noisy too, especially if they get wrinkled. Some of them flap like flags in the wind, making a healthy bit of noise. Vanes that are torn or have come loose sound like buzzbaits going thru the air. Vanes with holes in 'em whistle like a tea kettle.
Feathers do stabilize arrows quicker out of the bow. They also fold down as they pass an obstruction, and spring out after passing it. That means feathers are less likely to deflect if they accidently contact your arrow rest on the shot, or brush a stick on the way to the target. So, feathers are easier to tune and, where fletching contact can make a vane fletched arrow go nuts, the feather fletched arrow will stay pretty much on course.
Vanes are waterproof, but feathers can be treated with water repellent products.
The ONLY advantage vanes have over feathers is purchase price. The better quality vanes are half as expensive as feathers. However, COST is not the same as purchase price. When I can use feather fletches for two years and only get two weeks from a set of vanes.... That means, over time, vanes cost me 26 times as much as feathers do.
Think about it.
Check out this webpage. It's from Trueflight Feathers, so you know up front it's got a pro feathers slant but, honestly, I can't find a whole lot on this page to disagree with.
www.trueflightfeathers.com/facts.htm