I have a Model 3 that we got in the early 90s. At the time JD didn't sell them with hydraulics. The only piece they sold was the threaded piece that the cylinder screws into. We built our own hydraulics and portable stand. We also got dies for tubing from .75 to 1.75. I still use this machine today. Still works perfectly and makes very nice bends. I have used a Model 4 as well. I find it to be big and clunky, more difficult to use than my 3 and not able to do as much due to it's size and design. I've never used a 32, but the JD site describes it as a very heavy duty version of the 3. The pictures match the description.

All we do is drag race stuff. My 3 will easily do 1.75x.134 wall DOM and 1.75x.083 4130. And we use it for smaller brackets, mounts, and parts. The 3 is easy to use and be precise with, compact, and makes pretty bends. I would not trade my machine for a 32 because I think the extra heft and size of the bigger machine would hurt more than it would help. Unless you expect to get into large, very heavy wall stuff, I would stick with a 3. Sometimes bigger is not better and can actually be a PIA if you don't need it.