reliability? how do we know they are reliable if they are just getting on to the market?
How unreliable is the older generation pumps and hardware? do you mean, spill fluid all over your motherboard unreliable, or stop pumping and cook your CPU unreliable?

this is kind of why I'm a bit shy of one of these, an air cooled system gives good temperatures as far as I'm aware and is much less likely to fail. even if the fan/s fail the heat sink will still promote convection.