Most 4WD bearings a pretty much the same, so I don't know why he would have had an issue with the Rangie bearing. The only thing to watch out for is the model, as there are two different hubs, oil bath and greaseable. The bearings are the same, but if he did an oil bath hub, then it can get messy lol.
The 3.0L GU only really has a problem from lack of maintenance. The MAF needs regular cleaning, do not use non genuine air filters in dusty conditions as once they partially block, some of them suck the sides in and the dust bypasses them and destroys the turbo. Genuine air filters don't do that. Keep the fuel filters changed rehularly as well, as they can bypass when blocked, then they stuff injectors and the fuel rail (on common rail). Same as contaminated fuel, they have a sensitive fuel pump, and if any water getis into it, it will die (common rail again) and the fuel system si about $5K to replace - pump, rail and injectors. The fuel rail has a pressure sensor in it, and you can't replace it on it's own, the whole rail has to be replaced. All this is from running 25 Patrols on minesites throughout the Pilbara and they were the weakest car we had out of 200+ Patrols, Hilux's, Prados, Cruisers and some Isuzu trucks.
I wouldn't go a leaf spring 4WD at all as the spring plates can hang up on rocks as they hang below the diff. Just my personal choice though. Pick the right line and they can be good.
Every car will have it's weak points and common issues, but if maintained, the problems will be less common. Most bad experiences are from vehicles with a pretty rough past, and if you can find one with good service history and parts that have been replaced when required, then you will have a good starting point. Otherwise you will be spending up big on replacing **** before you even start to build it. Don't buy the first thing you find, have a good look around and buy the best within you budget. We made that mistake buying the 80, it was already a turbo (Safari), but it had a cracked head that didn't show itself until it was at 110 on the highway. The yard my wife bought it from were good about it though, they paid for just about everything, they gave us the option of having them recon the head at their cost, or we pay for a new one. The car got a new head and they paid the labour and all other costs. So far so good, it's been 18 months and it's still going strong. A few niggly things to fix, but nothing major. (Touch wood).