What I look at when buying a reefer is the box. Make sure it's solid. Cracks that have a fresh repair could appear over and over again. Could become expensive pretty quick. Utility and Great Dane are the only trailers I would recommend.
As for the units Carrier and Thermol King are buyers choice. Some love TK other Carrier. FOr repairs they are the same, some parts on Carrier are more expensive then TK, same goes for TK.
We have both TK and Carrier. No complaints on both units.
W2W, The Truck Paper site has a good search program you can use. There were some good deals to be had when I was doing my search for a 53' air ride reefer, in fact 2 were in Brooklyn. I did my search on the eastern states the best deals were definately down south. I'm sure you must have been there already,just my 2 cents. Good Luck on your search for a fridge.