I wouldn't go with Ranco's. I bought five, two years ago
and two have already failed on me. They keep giving E2 memory loss error readings, and re-setting the memory will not fix it.
I have not used the Johnson Controls model myself, so I'm not much help there. I use AP racks and do like them, but you do have to put them together, which after spending over $1,000 is kind of a drag, especially when parts do not fit exactly as they should. You also have to supply the tubs, which wouldn't
be an issue with cages. I also have some of Boaphiles racks, which did cost a little more, but came fully assembled and with tubs, and are far superior on craftsmanship. It's kind of like comparing IKEA furniture with Ethan Allen's. Both work fine, but you get what you pay for. Another thing you might want to consider is if you get a cage with sliding glass doors, a small
King Snake may be able to escape from between the pieces of glass. One thing I will say about AP is that their customer service is outstanding. If you have any questions, such as what size cage, and what type of cage is most appropriate for your snake, they will be very helpful. I hope this helps.
-Phil
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Work is the curse
of the drinking class!