This guy gives a good rundown about the FZJ80.
Specific to the 80, it's what happens when a car company sets out to build a bullitproof, spacious, purpose built, off-road focused 4wd with a low priority on fuel economy and 0-60 times. Specific to overlanding, an 80 is very reliable, strong, dependable, comfortable, capable and simple.
Easy to work on and familiar worldwide.
Comfortable like a newer truck, simple and mechanical like an old one.
No, I mean No corners cut. Japanese built, Toyota in their finest hour.
Solid front and rear full floating axles
Full time 4wd (AWD on pavement, lockable diff in H and L)
Front and rear lockers! (option)
Fit 33s at stock height
Huge A442 Transmission taken from a Japan bus (+10000# payload) on 93-94
Bulletproof xfer case
Due to the overbuilt drivetrain and HD frame, it handles excessive loads very well
I've heard it was engineered to have a 500,000 mile lifespan or something like that.
But... Nowadays parts are expensive/not available. Also reaching 20+ years old, baseline maintenance is suggested, as is getting comfortable under the hood and under the truck and doing the work yourself. (Although learning to wrench really isn't a negative and is just as much a part of overlanding as is hitting the dirt.)