I came here today to ask the same question, hopefully you get an answer.
I have their cloner bucket on the way to see how it compares to my EZ Cloner. I have heard good things about it as a cloner, but other than a few pictures on a google + group (and his plants did look great) I have never seen anyone use deweys for a full grow. I have found 3-4 threads here where people talk about ordering them and how they are going to try it, but never a report back.
From the few pictures I have seen though, it seems most people are running 2 dewey misters in a single 5 gallon bucket. Not sure if 1 would be enough or if you need 2.