And then there's the other side to the story!
My father-in-law has a 2000 registered Discovery TD5 which he has had from new, and hasn't had a spot of bother with it.
Whilst I haven't owned the other vehicles mentioned, I have droven them during a National Towcar Awards event. I must say that the Sorento was a huge disappointment following all the hype from the Caravan Club. I commented upon this to one of the other judges, who remarked "it's like driving a blancmange isn't it?" I know what she meant. Apparently, following criticism of the choppy solo ride on early Sorento's, the suspension was altered (softened) when the vehicle had its face lift. That made a more compliant solo ride, but it was sloppy when towing compared to many other vehicles.
We also tested Shogun, Landcruiser(s), Jeeps, Hyundai, Ssang yong to mention but a few, all of which had their own issues for one reason or another.
The choice must be yours and what suits you. If you get a bad car of whatever make (as the previous post says, even on a new Hyundai) you'll curse it. If you get a good one, you'll be singing its praises. There's far too much heresay and media hype spouted about all vehicles. Some of the cars mentioned above, based on my own experiences I wouldn't touch with a barge pole, but owners of them seem more than happy.
It's got to be your choice. Have a good drive of both before you do though.