I have a buddy in Tennessee who went to school to be a LR mechanic. He fell in love with the mystique of them while working with me in Africa. After working at the dealer for a year or so he told me that they advise new owners of LR's to plan on spending about $5000/year on repairs and maintenance for their new vehicle. After all the work he did on his own LR and on other people's, he recommended all his friends in Africa to avoid LR's and buy Toyota's if possible. I used to love them, but got tired of working on them. I find that though the Defender series are capable off-road, they break down too often. I've been left stranded one too many times in a LR. I now own 3 Toyota's. My 95' UK spec turbo diesel Landcruiser is my favorite of them. It's been driven all throughout Angola, Zambia, Namibia, Bots and South Africa on nasty roads, through hectic river crossings and hasn't let me down once.

OP, I've seen a lot of guys travel overland in Africa in all sorts of vehicles. What continent do you see yourself traveling across? The most common vehicles in terms of parts availability on the African continent are Toyota's and Land Rovers hands down. Stay clear of Merc's unless you're going with the big trucks. My buddy has a twin turbo G-wagen in Angola and after 5 years he's trying to unload it because of how quickly it chews up parts. If you're looking to do anything in North or South America, you'd do well with a Ford, Jeep SUV, Chevy or Toyota. My experiences in Brazil and Argentina showed plenty of parts availability for these manufacturers. I don't know much about Asia, but I'm guessing if you go with a Toyota or LR, you'll have parts availability more so than an American make.

Good luck on whatever you choose! May your feet always find solid ground beneath you.