I have a JET 13x40 belt drive. It has suffered from centrifugal switch/switch plate/capacitor issues. The placement of the centrifugal switch for fan shroud clearance can exacerbate these issues. It may not be an issue at all with yours because my lathe has some age to it so things might be different. I am still on the original replacement motor when that was replaced under warranty during the electrical troubleshooting in the first year.
The 3 jaw as it came wasn't too bad. It was probably in the .003 range in the "off" diameters. I have since reground the jaws @ my collet OD.
I was a total lathe noob when I purchased it. The JET onsite warranty repair was golden for me due to the electrical issues. I assume that is still standard with JET. That may not be as important for you given your experience.
The machine was fairly tight when it arrived but it is still an import. I once had a gear simply fly off under the cover because it wasn't properly secured. The half nuts on these imports are often not machined very well. Mine was about average, but that might be a part to evaluate early on.
Changing belts to change the spindle RPM is a pain. Hopefully you sprung extra for the gear head.
I have a seal leaking, but like I said, it has some age to it now.
Nothing else is worthy of note that I can think of. Other than the electrical problems, it has been a very decent machine.