To give you useful information, one must know which years you are looking at. Then someone can give you a run down on what you need to look for in each chassis, and what to expect. This is especially true with the Ford chassis, as there were significant improvements over the years. For Workhorse around 2004/5 there was a recall on brakes that you would need to make sure was completed. Otherwise, you can look for how many speed transmission it had, although the 4 speeds are not bad.