[A/S] 12 Volt cooler question

["C. Hale" <chale@xxxxxxx>]

Hello,
I'm trying to decide whether to buy a small (15-17 L) 12V cooler to use in
my tow vehicle when not pulling my trailer, and to augment my trailer fridge
when I am towing.  
Right now I'm looking at a Coleman and a Koolatron.  Don't know the last
one.  I'm interested in your opinions about their relative performance.
Also, I don't know the Koolatron brand.  It seems imperative that I also
purchase a 120V to 12V Converter so that I can plug it in at home or on the
road at a campsite with shore power.  They seem pricey for what they do.
Are the 12V coolers worth the expense?  
Thanks for your input.
Cindy