You'll find that the 3.4 V6 is the common power plant in those trucks. The timing belt is a maintenance item at around 100k miles, so look to see if that work has been done (along with the water pump).
Both trucks came with an optional rear locker (more common in the Tacoma), and it would be nice to have that if you can find one. The 5 speed manual tranny is out there if you would prefer that over auto, but both transmissions are well built and reliable.
There are tons of minor differences in the model years; too many to list out. If you find one you are interested in, post it up in this thread and ask for feedback.
1976 FJ40 - green and mostly stock
1996 FZJ80 - not so stock