Both vehicles are a good design, with few glaring design faults- more little niggles like all Land Rovers. I only know about Discoveries, so here we go:
Which diesel engine do you want? The original TDI (called the '200Tdi') is a simple, tractor-like turbodiesel that is known for making quite a bit of noise and clatter. However, it is regarded by many to be the best Land Rover engine every built. Its economical, reliable, easy to maintain and has power/torque in all the right places making for relaxed driving on- and off-road- but don't expect blistering acceleration.
The engine was re-designed (1993, I think) to create the '300Tdi'. Its the same size (2.5 litre) and power as the older version, but it quieter, smoother and more economical. It is generally tough, but some had a manufacturing fault that damaged the timing belt- it needs changing religously at 65,000 miles- so check this has been done.
Between 1998 and 2004 the Disco had the Td5 engine- still 2.5 litres, but more power, more torque. No problems have occured with this engine, and the added power makes the vehicle very car-like to drive. It's much more sophisticated than the TDI engines but fuel consumption is higher (25 mpg, intead of 30-32). The engine is much more complex, increasing servicing costs.
Discos fitted with the 300TDI (1993-1998) originally had a fault in the gearbox which was quickly fixed- if buying a 1993/4 vehicle, check that the gearbox has been replaced/changed, and listen for a 'clonk' noise when changing between 1st/2nd.
Whilst on the face of it, 300TDI cars seem pretty bad, they are very desirable, being reliable (as long as the two problems above are attened to [and most have been], practicle and easy to drive on- and off-road.
Body rot (shown as rust and a white corrosion) can occur underneath the boot floor and the rear wheel arches.
On high-spec models (GS, XS, HS) check all the electricals goodies (air-con, electric seats, cruise control, seat heat etc). Later Td5 models are very complex with lots of systems with acronym names (ETC,HDC,ACE,ABS), and these should all work fine (it's best to get a vehicle inspection is buying one of these later vehicles.
Few Discos have been off-roaded, so damage is not common. If you plan to go off-roading, the only problems are the rear over-hang which can drag on rough ground, the height (which makes squeezing down narrow tracks tricky) and the fragile front spoiler. Some models have side-steps fitted, which are very useful but decrease the ground clearance.
Good Luck- a Discovery is an excellent 4x4- capable, practical and reliable.
:wave: Do you want a car or a truck? Do you want to go seriously off road, just muddy lanes or is it all only for show? You need to know exactly what you want the vehicle for before you buy it!
If you just like the idea of owning a Land Rover (and who wouldn't! ), the Freelander is the more friendly!