I originally sold this to Danny a few months back now (he has purchased alot from me actually) and I think that the MKI or MKII ar more robust than the MKIII.
They seem to last and not suffer from bad solder joints like the MKIII and do a nice job for accelerating a 4000D with ram expansion to 128M.
I never had any issues with this accel. in my 4000D when I owned it and assume it is in just as good as shape now. I think there were maybe not as many MKI's sold which would also make them more rare than the MKII or MKIII.
Just my 2cents!
