Yea, A LOT of us have.
NP435 is the easiest choice. You keep the original clutch, bellhousing, crossmember, driveshafts, etc. You cut a hole in the floor, bolt it in and go. About the only fabbing really needed is rebending the shifter to clear the dash. How it drives, well very much like the 3-speed you have now but without the linkage jamming. But you get a wonderful granny gear as well.
The ZF adds an overdrive. But adds a lot more work to install. Hydraulic clutch linkage is nice, but adds more work. You don't use the original crossmember. Transfer case is relocated, new driveshafts.