Ive made the mistake of purchasing one, it cools well enough, running it on a 8800GTX, a 6600 duel core + a hard drive cooler (Thermaltake AquaBay), everything is running alot cooler then it was.
The problem was in setting the thing up, (and still is the case to a certain extent), as initally it was constantly beeping at me that the flow rate was too low. I belive this *may* be due to air locks in the system, as it does now seem to have stopped that action after about a week of use. My main remaining problem is the fact that even when I shift it into manual mode it only ever get to just under 1L / min flow rate, which is half of what is stated for it (the dial goes to 2L / min, and its stated stas are 300L / hour).
Im not sure why the flow rate is so low.
The inital setup seems to require that the device is tilted up to around 45degrees multiple times to try and empty any airlocks, and while doing this I did hear the bubbling of escaped air quite a few times.
My other main beef with the system is that if it detects that the flow rate is too low, it sounds an alarm AND STOPS THE PUMP + FAN! which is freaking insane! it means I can never leave my system on now, even If I just want to take a shower as I dont trust it in the slightest.
This is my first water cooling kit, so any advice would be appritiated.