I own an FOP-32 and it did a great job for my Duron 600 @ 1000, but that was the limit for it. I am currently doing some experiments with the ThermoEngine and I must say that I am very impressed with the design. There are two or three unique design factors in it that are testimony to the engineering forethought that went into it. Still, it like the other, is an HSF designed around the 60mm fan footprint. The FOP, WBK, 6035 and ThermoEngine all perform much better when adapted to an 80mm fan. Any of them is a good choice, when paired with the right fan.
Hoot