I would hesitate twice and then hesitate one more time before placing any confidence at all in a manufacturer supplied number for a statistic like C/W, which can be so easily fudged, as we have seen.
But yeah, I've been out of the overclocking scene for a couple years, now. I have no idea how well heatpipe heatsinks perform, other than "better".
As for the danger of a large piece of metal spinning at kRPM, I agree. This is bad enough that there probably would have to be an safety interlock on computer case access panels that reverses the impeller to a halt when the enclosure is opened.
SPCR is a review site pretty serious about their methology; their newest heatsink reviews don't have °C/W figures due to difficulty measuring the power output of socket 1366 CPUs, but here's a mid-2009 review of a huge heatpipe/tower heatsink: http://www.silentpcreview.com/scythe-mugen2
Page 6 states °C/W values of 0.29 down to 0.14 depending on the amount of air pushed with the fans. SPCR's test fans are pretty low-flow to begin with (47 CFM/1080 RPM at 12 V), so you could probably go slightly lower by using real screamers.
But yeah, I've been out of the overclocking scene for a couple years, now. I have no idea how well heatpipe heatsinks perform, other than "better".
As for the danger of a large piece of metal spinning at kRPM, I agree. This is bad enough that there probably would have to be an safety interlock on computer case access panels that reverses the impeller to a halt when the enclosure is opened.