They work better.
They are lighter which improves FOC and creates a faster arrow.
They are much more durable.
They are much more forgiving with contact with objects.
They look sooooo much better.
They don't flap like a flag when traveling at 300 fps like a vane does.
They still work even if they have parts of the feather missing unlike a torn vane

Their only down side is wet weather but unless you are hunting in real rain it really isn't an issue and there are plenty enough water proofing products out there you can use.

I switched to feathers several years ago but I still keep trying the new vanes every year cause I need to be abletotell my customers what works and what works best. Guess what? I keep coming back to feathers. They just plain work better than vanes do and they look a thousand times better than vanes do. The only thing to come close, and they did come very close,was NAP's quick spin speed hunters but durability is still lacking when compared to a feather.

I personally like Truflite better than Gateway.