I was running the Dirty Dog rotors on my bike for a while. Super beefy and keep straight, don't get too hot at all. They slow you down well and get you plenty of compliments in the lift line. Link here:
I just installed them on my wifes bike. They have plenty of grab, so I dont think that is an issue. Only been on for a few weeks though, So the long term durability (and pad life) are still in question.
I use them, but it's for an AM application rather than DH. I'm very happy with them myself. Inexpensive, VERY lightweight, disperse heat very well, much more "bite" than the avid roundragons I was using before, and they look awesome. For DH, you'd probably want a bit beefier rotor with more braking surface than the windcutters I'd imagine.