I was talking to the person who did the OCworkbench.com review, and he said he had hard times stabilizing his cpu above 1.2ghz. Couple with 2cooltek's hard-time getting the heatsink to cooperate with his test bed, and seeming nature of how it "cheats" socket-thermsitor readings, I would say the heatsink is probably of adequate performance, but nothing to really write home about.
Mike