Minidisk is a great medium for the car. It gives great quality and instant track access so you don't spend time forward and rewinding all the time. The 6500R is the most affordable MD unit I found and has all the sepcifications I imagine anyone would require.
Installation into my Rover 200 was a breeze and I can even buy a £30 adaptor to enable my steering wheel volume controls to work it.
The sound is clear, it hasn't jumped so far and it has ample power. The dispaly looks good and the radio has all the useful features like RDS. The only area which i think it could be improved is the method for removing the front panel. I find it a bit fiddley, although I may get used to it.
Overall, great piece of kit at a reasonable price.