Hi
my two cents. if your looking for a 12v cooler that will be more efficient and give you years of life, 400 bucks in all likely hood will not cut it. I currently own 3 45-50's. Two arb's, and one engel. Work awesome. I also had tested a 375 dollar used cooler and I wish I had not. So, my opinion is you find a used quality fridge/freezer and pay the additional cost for long-term satisfaction.
Remember: You get what you pay for. Works most the time.
Now, if someone out there is selling one of these quality coolers for cheap, thats another story. Just get Quality up front and save your sanity. lol.