Maybe one about the buffer effect of aio coolers. For example, if all you do is basic web browsing and office work, you can keep the fans way down. It takes so much heat to get the water temp to climb that the fans won't ever have to ramp up and down to keep up. Keeps the dust out of your computer and the noise down. If you are a hard core gamer, you will get amazing temps, but then as time goes on and heat builds, then you end up with decent temps still, but the fans have to ramp up to keep the temps down just like an air cooler, effectively gaining you..not much over an air cooler. Then after you stop gaming it takes a while to get the water temperature back down because it takes quite a bit to pull all that heat back out of water.
Also WHY in the world do the fans on an AIO cooler ramp up based on CPU temp instead of Water temp, that is so annoying and pointless unless you are running it hard for a long time, it's stupid.