As long as you buy new dont worrry about the brand too much, new gets you warranty.
Used, exposes you many scammers selling broken chillers as working. To buy a used chiller you must see it in operation, must know how to test a chiller to ensure it works and a bucket or bathtub test does not suffice.
Buy new, buy one with built in thermostat and controller.
Why do you even need a chiller? Canopy fan, stand fan, window AC
Are you running metal halides, if not, rethink