Neto,
I bought two used Dolphin Diagnostics about 8 or 9 years ago.. I used them in rent house pools and they were just retired the beginning of this year.. I did have to replace the tracks and bearings, but all and all, they worked well for over 10 years. I also had a Dolphin Premier at my home pool that I used for about 5 years before moving it to a rent house and it still works just fine.
The old Diagnostics have been replaced with the newer S200, which is a much better machine. No problems so far, but they have only been running about 8 months..
Thanks,
Jim R.