a very good friend of mine and the guy i wheel with the most has a 2004 LR discovery. i help him work on it a lot (that's a sign lol). they are indeed very capable vehicles off road, but it's a different kind of off road. i would never try anything remotely fast in his rover, but it's cake in the taco....on the other hand...you can get a TON of flex out of those things. the solid front axel and coils all around are great. OME makes a great 4 inch lift for them. pair it with coil spring retainers and you'll have more flex than you can use on most trails.
the cons, like you said are the durability. some minor things (mostly electronic) like the power seats not working or various lights going out when the bulbs are still good, and some major things, like the fact that his leaks everything. we've replaced about 6 different seals/gaskets on that thing. head gasket and exhaust being two of them.
for refference, it has about 80,000 miles on it and the guy he bought it from didn't wheel.
with all that said though, it looks like a good rig at a decent price. as on all CL adds though, make sure to talk him down as he's not expecting to get 6000 out of it, just hoping it won't be negotiated too far below that.
good luck and have fun if you get it