Most of PUREOC watercooling members use Apogee GTZ and HK 3.0.
GTZ was the king until HK 3.0 was borned but if you follow Gabe's (Swiftech CEO) thread and Shane (Hesmelaugh) CPU blocks shoot out then you will see clearly who is the king in the CPU block.
It's coming soon........http://www.swiftech.com/assets/images/products/apogee%20gtz/apogeeGTZ-x400.jpg
can't wait to see the review and results comparison with the GTX.
Update: It is here, you can find our own review by click this link http://www.pureoverclock.com/article655.html