neither body lift nor suspension lift gain you any ground clearance.
the front crossmember only gains ground clearance by getting larger tires.
the rear axle pumpkin gains no ground clearance, unless you get larger tires.
the torsion bar brackets only gain ground clearance by installing larger tires.
the Superlift suspension lift doesn't give a better ride, or anything like that, since it re-uses the torsion bars. So you still have the same amount of wheel travel and same ride.
The RCD lift, if can be found used, will definitely help with the ride due to the swap to coilovers, and removes the dragging torsion bar mounts.
the only 2 downsides (imho) to the 3" body lift is the steering extension, and the fact that there will be greater tension on the longer body mount bolts in a crash.
upsides to a body lift is, much much much easier to access O2 sensors from below the vehicle (no needing to rip out carpet, center console, etc). Much much much easier to remove the t-case to transmission bolts if needing to remove the t-case (no needing to rip out carpet, center console, etc). Much easier to change out spark plugs through the wheel wells, too.