Matt - there might be a lot of people out there, like me, who've never heard of these things before. I've just had a look at the website, and I can see that they might be useful to someone doing second-operation jobs who need to accurately reset workpieces. I suspect that a lot of CNC users don't work this way; one setup per workpiece where profile and internal machining is done at one setting is more common? I'm thinking out loud here, but that's the way I usually work. Vertical mill (mine is still manual - CNC conversion is on the list...) is a different matter. However, I find a conventional wiggler very quick and easy to use. Haimer seem to suggest that calculating half ball diameter is a complex, difficult, job. Maybe US education is a little different from European education, but I don't find calculating half of 0.2500 to be so very difficult. I don't even need to use my fingers to count or anything. And with a DRO, pick up the edge, switch to imperial, punch in 0.125 (+ or - as appropriate), and if necessary switch back to metric. And using a wiggler with a DRO to find centres is trivial.

Haimer seem to be talking of commercial systems where you can permanently put the edge-finder into a toolholder, and I would guess that this takes out recalibration every time you pick it up. Me, I'm swapping collets all the time and I would expect to recalibrate because I'm not sure that ER collets are that good. The wiggler is beautifully self-calibrating. But I don't have customers paying for my time so the time/money calculations are somewhat different.