You have to use the one that would best suit your needs.

1. - Feathers are more forgiving than vanes as far as rest clearence goes unless you shoot a drop away than this point is null.

and

2. - Vanes are much better in harsh weather such as rain whereas feathers will tend to lay flat when they get soaked. and vanes are much more durable and last longer.


so it's really up to you as to which one better suits your needs, good luck.