I own a 1986 model 110 (before they were called Defenders). It is a bastard, since the original engine, the 2.5TD, the worst engine Landrover ever built, has been replaced with the 200TDI engine of the 1996 model. This engine again is, together with the ROW
(rest of the world, as opposed to the EU and US versions) and British Army version´s 300TDI, maybe the best and most reliable engine Landrover ever built. As long as you replace the timing belt every 80.000 to 100.000 km and make sure that there is always enough oil in it, it will run forever. Unfortunately this engine, with it´s mechanical injection pump, doesn´t pass the EU and US emission tests. The newer TD5 (5 cylinder pump nozzle injection, electronic control) and TD4 (4 cylinders common rail engine, built by Ford) are less reliable and they are not really repairable in the field.
petrol engine delivers a lot of torque, but unfortunately uses a lot of fuel as well. I politely refused one because I don´t own an oil well. The diesel models are relatively economic with 9-11 liters for 100 km for a 2.5 -3-5 ton vehicle.
The basic design of the Defender is great, but, like many British cars, it suffers of sloppy manufacturing. One issue is corrosion of the internal door frames (due to historical reasons the body consists of aluminium sheeting over a steel frame), because they never isolated the aluminium from the steel, leading to dissimilar metals corrosion.
Older Defenders also suffer from electrical problems due to mthe use of components by the British manufacturer Lucas Electrics (Sir Lucas wasn´t for nothing known as the "Prince of Darkness"), though it became better when Bosch bought the company. Also Landrovers tend to leave oil stains wherever they are parked.
Most spare parts are very cheap, at least here in Europe, mainly because the truck´s main use as a military and utility vehicle, especially if you buy generic or aftermarket parts and not those with a LR
logo on them.
Same as with the older Toyota Land Cruisers (aka the Bush Taxi), there doesn´t exist a proper replacement for the Defender. The trend goes to yuppyised wannabe 4x4 vehicles for cities. The German mountain rescue organisation has been forced to b uy old Toyota Landcruisers abroad and to modify them locally because they can´t find any modern truck suitable for their needs. Possible replacements might be the Tarpan Honker from Poland and the Iveco Massif.
The Defender is a slow truck on the road, so better get used to drive in the truck lane. If drive at more than 100 km/h
it becomes very noisy inside. It has a high centre of gravity, so if you go into a curve too fast, you can topple it over.
The springs arer very hard, because the truck has been designed to carry a ton of cargo. A few hundred kgs in the back make the ride much smoother.
Be prepared to do a lot of maintenance yourself, like lubricating the prop shafts every 5000 km and also, if it is a model with an older LT77 gearbox, to remove the transfer gearbox input shaft every 5000 km to lube the internal splines with grease or else you´ll end up with an expensive gearbox change due to wear of said splines. From a certain model on (I can´t be @rsed to look it up now) LR
introduced to holes in the shaft, which allow gear oil to reach this area. Working under the car is quite easy, because there is lots of space.
You also have to adjust the rear drum brakes from time to time, butthis isn´t a big job.
I´m 6 ft tall and weighabout 87 kgs and I´m quite comfortable in the driver´s seat (with the seat fully back, there exist extensions for the seat rails, but I don´t use them). After long distance driving I feel more refreshed in my Defender than in a modern car in this semi reclined armchair position).
Hope this helps.