Both can be recommended but as with any custom loop kit it is only as good as the person who puts it together. Have fun and take your time.... I used an old FX 3000 build to practise on my first loop, and yes it did leak 😳
Both are good. As someone who has reviewed both EK and the Corsair Hydro X products for Tom's, they are each quality items. Much of it depends on your choice of aesthetics and design.
Also consider Swiftech, Alphacool, Koolance and Singularity as well as Bitspower and XSPC.