Nope, though have you checked bundymania's review of the 79 series waterblocks? He really liked the komodo and it was one of the best performers, not that there's much difference nowadays.
Nice, isn't it. I'm sorely tempted (the cooler on my 7970 is slowly driving me INSANE) EDIT: so insane I forgot to close the bracket
I have the hydrocopper on my old gtx 580, it seems to do the job well, so no reason other blocks by them shouldnt be bad.
Nearly all blocks perform within a degree or two of each other, it's mostly a case of aesthetic choice and price.
Got one of the 580 blocks on my 570 sitting here idle, it fit beautifully and the interior has a lot more surface area than the other blocks available. Gave my wife the 580 3GB, she's using the everliving hell out of it. Best decision I've made in a long time.