Don't know for sure what your needs or thoughts are Bruce. Second-hand Bridgeport mills are out there, and some are no doubt in fine condition, while others are undoubtedly junk, or near to it. You need to ask yourself if you have room for a full-sized Knee Mill and do you have 220 service available? How much table do you see yourself needing, and how much travel?
I've been quite happy with my Grizzly G0704 that I have added a DRO to, but it is still just a hobbyist type bench-top mill at the low end of the potential commercial usage range, and it certainly does have its limitations!
Grizzly G0704:
https://www.grizzly.com/products/grizzly-7-x-27-1-hp-mill-drill-with-stand/g0704?