While looking nice to the person who cannot fit their own proper nut. That ABM nut has its drawbacks from the technical point of view.
Consider how the nut must be slotted? Do the screws sit at a slight angle so that no matter how they're turned, you have the same break point?
Look at that one by Atlansia. The break point, not sharp, and in the middle of the screw! Might be ok for bass, forget it on guitar.
For the price and long life of the nut marterial out there today, why not just fit (or have fit) a proper string nut and be done with it?
I like the pre-slotted GraphTech on most guitars... BUT... I only use the slots as a guide for fitting and final placement of the finished slots. That is, I square up the bottom, then take material off the top to fit the nut, using the slots as positioning guides. Invariably, the molded slots will be cut away and never seen when the proper nut elevation is achieved. The last two necks I have gotten from Warmoth have their own slots fit. We'll see how they do. Kens pretty much a perfectionist, so I'm sure they'll do ok.
The Warwick design is the best pictured, imho, but even so, I'd rather have a nut that rode on shims and locking screws, than screw pillars.