I've had a Silverado. It worked fine for my Duron600@933, but didnt cut it with my Athlon 1.4 (>60°). Strange enough, my brother also has one, and he has no problem with his Silverado and Athlon 1.2@1.4 (<50°. Never figured out why, since my case temps are better, and I reseated my HSF more than once..
Either way, I now have a Swiftech with a Papst fan. Im VERY happy with it. makes less noise than my Silverado (yes, even less) thanks to the extremely low noise Pabst fan @1800 rpm (i think). It also cools pretty well, keeping my Athlon 1.4 between 41 and 46°C. It even seems its so effecient it can do WITHOUT fan.. (although at pretty ugly high temps). More info later on..
There is also no fear of clips breaking off, or crushing cores, thanks to the 4 bolt mounting mechanism. Highly recommended and very expensive HSF ;-)
---- Owner of the only Dell computer with an AMD chip