All bias aside, remember that I own an 80 as well as wheel with many who own very built Landcruisers of all models.
I have an "early" FJC (bought in April '06) and have done some fairly extensive and challenging travel in it. I've got 55k on it now and without jinxing myself, haven't had any issues. Now, I did swap out the "questionable" rear ring & pinion before doing Rubithon '08 and saw 2 people have issues in Moab on the same trip. In both cases, there was some "hopping" of the rear end, while locked, not a good idea IMHO.
The whole fender "bulge/rip" issue seems to have been an isolated issue without any common factor of lifts/wheeling/tires being able to identify why they have occurred. I haven't experience this issue either.
I'd simply say its a Toyota and have found excellent build quality with mine.
If I had to choose one or the other, it would be a tough decision. I believe that the 80 series has more potential in being set up for either hard core wheeling or expedition travel. The room is great, the live front axle is better, there are enough suspension options to make it a great rig to off-road. But, its slow, sucks gas in a big way, I hate the way Toyota placed the cats and is heavy.
The FJC wheels great for the type of use you plan on, right of the showroom. In fact, I think thats what Toyota really planned the vehicle for. For two people and a couple dogs, its great with plenty of cargo room to enjoy most anything outdoors. For more hard core wheeling in the FJC, it takes a significant investment and it still is arguably "hamstrung" due to the IFS front end. For expedition type stuff, you really wouldn't need to do anything to it but fit your drawer system to it and go. Upgrade your tires to a 255/85/16, put some OME suspension on it and you have a great vehicle that can go most everywhere but the "extreme" trails. I think that ATRAC is an excellent feature, so no matter what you do, if you get an FJC, make sure it has a rear locker so you can get ATRAC. Remember that if it has the rear locker, it is "wired" for ATRAC regardless if the switch is installed. I bought the ATRAC switch and for $50, I got ATRAC.
Sorry for the long reply. In all honesty, I'd probably go with the FZJ80 if I was FORCED to choose one or the other. I love my FJC, have pushed it to the limits but it falls short with the IFS when it comes to "serious" off-road capabilities. It doesn't mean the FJC can't be made to accommodate that short coming, it just comes with the expense and risk one must take with it.
Hope this helps and if you feel like driving down my way, you could take mine for a spin if you wish...