Adalan,
As with any vehicle, I'd make sure you had full records for the services performed on the vehicle. Ie, was the coolant changed every two years as well as the brake fluid?
There are plenty of Discos for sale, so be prepared to walk away from any without records and let someone else deal with it.
If you're in the US, Bear Valley Land Rovers has a nice website with good prices (
www.bvlr.com) that might come in handy when comparing what you can find locally.
Personally, I'd opt for a full workup, including a compression test before plunking down that kind of money on a used vehicle. This kind of pre purchase inspection will usually only set you back $100USD...also, it might be a good idea to have a LR stealership perform the inspection...since they *should* know about recalls etc.
As far as a Jeep, I'd assume you're looking at a Grand Cherokee to be comparable. Everyone I know who has one loves them. Maintenance/recall issues seem to be on par with the Disco though.
Bogatyr