Someone I know currently has a H70 although I told him that the H70 is kinda weak water cooling and is not a "true" water cooler. So I suggested one of these coolers, but I'm wondering which is better due to that one is closed loop and the other has a smaller radiator. Which is better, the H100i or the XSPC 450 RS120?
If your radiator is inside your case, it sort of defeats the purpose. The closed loop is easier to install, so with those two choices I'd go there. Neither of those are really a significant improvement over an aftermarket top-end air cooler temp wise, only noise wise. Except that you need worry less about clutter and may upgrade later.