Regarding SStone's remark about not trusting them to keep milk (or
more importantly...homebrew) cool for more than 12 hours, let me
throw in another two cents in...as well as gain another number 
on the leader's list...

These coolers keep the contents approx. 40 degrees cooler, or
in the reverse mode, 40 degrees warmer than the outside temperature.
Last year on the EuroVan's maiden voyage we ran our cooler in the
van as well as in the hotels constantly for 12 days...never had
the milk sour, the wine or beer warm. I have the utmost faith
in them....

Ric