Very impressive indeed. I picked up the Scythe S-Flex 800 RPM fan for a HTPC I built with the goal of complete silence. This fan moves air that is barely noticeable to your hand and to have this super low air flow get within one degree Celsius of Thermaltake's flagship cooler running at 1250 RPM is amazing. We are talking LESS than two-thirds the RPM and the same performance.
FULL STORY @ OVERCLOCKERCAFE (http://www.overclockercafe.com/Reviews/cooling/ThermalRight_Ultra120_Extreme/index.html)