Did you ever get a response on advantages or disavatages over the centroid dp-4 probe? Im extremly interested as im ready to buy one as well!
Wow, that was 1.5 years and a kid ago.... I don't even remember typing that. From what I remember about the research I did on probes is that most probes are probably better than our machines, but that also depends on if you know how to use them. Also, you have to pony up for the "digitizing" software package from Centroid if you want to use them with the Acorn for anything but corner finding. This is why I didn't buy a probe, I have had other priorities with the machine over paying that much to probe.
In the end, I decided I would likely go with the Drewtronics S5000LED. It's cheaper and the resolution is good enough for 99% of what I do. I figured for $170 you can learn how to probe and decided what probe is right for you.
PZ