I'm open to either way as far as the roached manes go... though my pony has always had a long, lovely golden mane and it would be an absolute pity to take it off. During the summers I usually braid it so she doesn't get too hot. Summers here are relatively mild, too.
On the other hand, winter here is muddy muddy muddy. I usually cut off my girl's feathers during the wet miserable months because they just get caked with crud and stay moist and that really doesn't seem good for the well being of her skin.
There's a Freisian owner at our barn who painstakingly brushes out and blow drys
her boy's feathers rather than to cut them off during the winter. She was convinced that feathered horses have feathers for a very distinct reason and that cutting them off is somehow really bad. My pony has been just dandy so far.