My 04 Disco has a Visteon 6500. There is a 5500 model as well, the 6500 having a CD player instead of the casette player. That's of course what the lower spec models had in them and they are quite adequate. Depends what type of head unit was fitted with your spec of car really, could it have been the high spec Harmon Kardon system?
I think that most of the aftermarket units are too blingy. Probably a sign of the times where many factory fitted units are now pretty good and it's only the young petrol heads want to change them, and of course there, the more garish the better.