I had air bags on my '95 F-250. They worked well, but one has to have a simple method of adding and removing air when needed.
My '06 F-350 has Timbrens. Very simple. They only work when the truck is heavily loaded and then they do the job. The Timbrens usually come with some spacers that can be installed or not installed depending on how you plan to use the truck. Mine are set up so that they engage when the bed load is about 1500#. This seems to work OK. No need to do any adjustments with air pressure.