Just to correct here :
AG and ZirkonZahn do not make scanners, they are SmartOptics (germany) scanners.
Now, as some might know, we have done an extensive study of multiples scanner in regards of precision, predictability, speed,etc. (over 15 scanners were tried by the way, only top of their line for each brand)
Medit score highest with the T500 within all value equal with 3shape E3
DOF HD was less accurate by few micron, but overall a super nice scanner and super fast
I couldn't put my hands on a E4 during our extensive testing
Medit also have one of the best interface, but that could be an opinion more than a fact (thing said, the 3 persons involve in the testing, we did prefer Medit interface)
I am waiting for my T710 and will try to get an E4 to continue our testing, pretty sure T710 will rock them all (little finger telling me)
Best of the buck I will still strongly suggest T500 or the new T710 for sure if you can get one (still new, a lots of orders going)
Don't get me wrong, DOF HD is a good scanner, at the end if you have a good price, good feeling with it and important a very good supplier, you will not be disappointed.
NOTE : This comments IS NOT PAID BY ANY SCANNER COMPANY
NOTE : All desktop scanner was compare to an industrial scientific scanner with a precision of 1 nanometer (1000x times more precise than any of the desktop scanners used during this testing)
NOTE : Yes MEDIT T500 is the scanner we use in our production facility to scan the wax-up of implants bars case, our implant cases are scanned with the nanometer scanner, we appreciate the Medit T500 because all 5 of them run 12 hours a days non-stop and none have broken since we use them (almost 3 years now)
you understand the whole purpose of my study was to pick what scanner we would use within my own company, as you can see we do thousands of scans per month so it had to be precise, fast and reliable and I am known to be SUPER FREAKING PICKY