F450 with liquid spring would be my choice. 4x4, good turning radius, plenty of power. No more or less reliable than anything else. Liquid spring on any Type 1 chassis is a must.
Have worked in Dodge 4500s, Chevy 4500 (the old kind, not what is out now), E450 chassis, and Chevy 4500 van chassis. Of those I pick the F-series. Never worked in a medium duty (International, freightliner) and don't see why you would want to, the boxes are just not that heavy.
Always like Lifeline boxes. Braun NW, Braun, Excellance, Horton, Frazer also seem to make nice stuff.
Not impressed by our AEVs or Wheeled Coaches. You get what you pay for.
Also worked in Leaders, Demers, Medix, Osage, and McCoy Miller which were meh, although honorable mention to the Demers for surviving a long career and then getting the crap beaten out of it at a busy AMR op.