Hardwarecanucks posted a review of the highly-anticipated Thermalright XWB-1 CPU Water Block

At the end of the day, it comes down to the individual user. This block looks great, and provides the best out of the box performance in a high flow loop. If you're running a low restriction PA120.X radiator with a high flow pump (D5, DDC w/Petra top, or Iwaki) and nothing else in your loop, the XWB-1 is the block to beat.

Thermalright XWB-1 CPU Water Block Review