Most of them fly great... they just don't impact where field points do. Mechs don't really either for that matter. 95% of shooters cannot tell the difference (me included) but anytime you increase surface area and frontal drag... you are going to have a difference.
I have found that Slick Tricks do about as good for me as any. I've had good success with Montecs, Thunderheads and even Muzzys in the past, though Muzzy's can be tempermental.