I bought 3 5x3 caddies from xcase a few months ago and the stock fans were a touch too loud so swapped them out for silent fans (Coolink SWiF2-801 's ) and must say i'm impressed with how silent they are (quieter than my htpc built a couple of years ago LOL).
On a side note the caddies only come with enough screws to mount the drives in the caddies and NOT to mount the actual cases themselves (even though you can use the same screws) - I e-mailed customer services as the screws are a specific type - too deep and you risk damaging the drives in the caddies to small and, well you get the idea - They sent me all the screws I needed FREE (this doesn't happen often LOL) - I can only say from my experience xcase have come up trumps and (touch wood) have had no problems with them.