Even though the NH-L12 Ghost S1 is designed primarily for the Loque Ghost case, if you have mini ITX case, do not hesitate to go for this version. The smaller fan can give you extra room for RAM, while it does not affect the power. If you want to experiment a little, you can calmly put on Ghost S1 even bigger 120mm fan, and suddenly there´s a powerful cooler. As expected in the beginning, the NH-C14s worked with a little less powerful processor without any problem. It is clear, that this cooler can be used with almost every processor.
All coolers proved that they all fit in the ITX builds – yes, even the NH-C14S ( for example, you can install him in the Fractal Design Era) but of course you have to think in advance of what kind of processor you are going to use him for. The NH-L9 is not suitable with more powerful CPU but it can handle a less powerful one without major problems – of course if you do not mind a noise little bit louder.
From my point of view, the NH-L12S or the Ghost S1 edition is the middle ground for most of the CPU and even if it would not managed it in the best way, you can always use the 120mm fan and you will have a better cooler at your disposal at once.