What do you require from it? My Scythe Kaze Q12 has done it's job flawlessly and it's really cheap too! It can run 12 fans and uses 3-pin connectors (which work with the 4-pin ones too). The only downside is the rather unexciting look of the thing: http://www.scythe-eu.com/en/products/pc-accessory/kaze-q-12-lueftersteuerung.html
I am looking for a controller that can control between 5 and 10 fans, motherboard supports 5 fans so would only need controller for 5 really. Looked at the corsair link system but very mixed reviews. I am currently running 5 corsair 3pin fans.
This is one of the ones I had looked at but I read it pulses the fans rather than keep at a constant, and my minuet understanding is this isnt good for the fans