I think the Corsair unit is
way better
The Corsair doesn't need the biannual flushing

Corsair unit can handle up to 200W of cooling
Corsair unit is external as well -- also uses the same type of hoses as the koolance
Corsair unit will come with the Northbridge and Video card coolers "soon"
Corsair unit has Corsair written all over it

-- AKA Xtreme Water Cooling System
Finally, Corsair unit costs way cheaper than the Koolance EXOS because the EXOS doesn't come with the CPU block, the Corsair unit comes with it. Monarchcomputer.com has it the cheapest @ $200
Read my review
here on TIMO.