Most any good brand of cooler will do the job. The thing about trans coolers is they make many different sizes depending on vehicle weight and towing capacity. I suggest going with a cooler that is a step or 2 bigger than your car's weight class. It's the German in me wanting to over engineer.
And buy one that is thermostat controlled. That way the cooler doesn't allow trans fluid through it until fluid temp has warmed up sufficiently. This will allow for winter use without over cooling the trans fluid.