Since the goal for my modeling is to soften 90 degree corners to catch highlights, I've started using chamfers instead of fillets.

I end up accomplishing the same effect without the added polygon weight added by fillets.

Granted sometimes you want a round edge and can't do without the fillet but for my spaceship models and buildings etc., I can get away using the chamfers - my models feel way lighter as a result. Usually they're easier to edit in the polygon editor as well!

-Will