I have a Tunic T on my e6600 and it works well -- no problems there and if installed properly (took me a few times) it really does its job well. The fan on that beast on anything other than practically off is LOUD however. But the Tunic works wonders even on its lowest settings.
Now... for my X2-4800+ which I OC to 2700mhz I have my trusty Big Typhoon... the original one. Even with that fan at 100% it is SILENT.. DEAD silent. Again, took me a few times to install it right, put the gew on properly etc but it was all well worth it. Idle is 29c and reaches about 44-45c on Orthos full load. Again it is a pleasure to own. With my Antec Sonata (first generation), which has only one 120mm fan in the rear set at around 35% and ATI x1950XTX Crossfire and a x1900XT with both the fans changed to aftermarket ones and another 120mm fans behind the cards... it is still virtually silent. Compared to my e6600 mentioned above with the Tunic in my Antec 900 that thing is LOUD. Even with the 4 x 120mm fans set on their lowest setting the eVGA 8800GTX and the 700W OCZ PS I have it's loud. I have to figure out what the heck is the problem. I know the 8800GTX is actually not that loud under normal use.
Anyhow long story to say either the Tunic on low setting or the Big Typhoon at whatever speed... both are amazing.