OK.. the defenders are fairly reliable, up to some extend tough and well buildd and with good off-road capabilities. However the part are not easily avalible, fairly expensive, they become alot more expenive to maintain than a similar Japanese model and are really overpriced.
I know most of this from a mechanic that worked for 25 years for the UN, here in east africa. The comparable japanese models are much more reliable, cheaper and they last longer with less money.
You might not get the 'safari looks', but where is that gona get u when ur trans goes out after only 70 000km in the mountains of Afghanistan... hahaha... good luck finding the closest Land Rover dealership... and then waiting 3 weeks for the part.
My recomendation.. buy a 2 year old Nissan Patrol.. they pretty much last 4ever.