I wanted to try IC Diamond but I wasn't crazy over how it scratched the heat spreader and heatsink. 4Ryan posted this last week and it was enough to make me not want to use IC Diamond. I know it's not that big of a deal but again I don't like that it scratches also it would void your warranty and make re-selling harder.
A valid point. But the IC Diamond is doing exactly what it is supposed to do, it permanantly fills in the imperfections on the surface of the CPU/GPU. Removing it also removes the imperfections.
Besides, I always either sell my old stuff to a friend or give it to family members. And as a longtime overclocker and builder I have had DOA parts quite a few times but never had to use a warranty on a CPU.
I usually buy EVGA graphics cards and they have the best warranty in the world, covering overclocking and even moding the HSF. The only company that does as far as I know.