I got the cokin cos it's the P type and basically mounts onto the lens via an adapter. This way, it doesnt bother me what sized the lens is : 67mm, 72mm, 77mm etc.... Basically, it's cheaper... haha.... about $37 from CP.
For the Hoya one, it's more ex and also specific for a diameter only. It looks like a normal filter save for the glass which is an IR pass material. Not sure about the price, but remembered it's $100+