Don,
Regarding putting a container in a pan of water, I tried that last year with pots, keeping the pot base filled with about 2" of water all the time, and it turned out to be a total disaster! (See photo below) While the plants did well for the first month or so, half of the tomatoes developed blossom end rot (due to a constantly saturated soil). Live and learn.
So I am using those pots this year (sans base) to grow Maui onions only. All 48 of my tomato plants will be in EarthTainers this year.
There is a good video on how the EarthBox works by Blake (its inventor) at this link:
http://www.earthbox.com/consumer/videos.html
Also, regarding water use, it is my understanding that an EarthBox type container will actually use LESS water than an in-ground plant. The plant drinks in only the amount it needs, and no more. People reporting having to water daily likely have built their EB will a small water reservoir. Again, I am totally sold on the AWS as the best watering solution.
Ray