Carmenie Stemmler asked about the D.E hive design. 

Chris Slade said: 
I have looked at the design of the David Eyre hive on his web site . . . 
The innovation is the ventilation system which I have not tried but is on my
very long list of things to do.

And Garry Libby said:
I have two D.E. Hives and I think they are great. During the hottest
days of last summer when My ten other hives had huge beards on the front, My
D.E. Hives had none, this is due to the great ventilation those hives
feature.

I also have the conversion kit on one hive, then, as I am a hobby wood worker tried making an 11 frame D.E. hive to - as I have a significant investment in Peirco frames(sorry Dave).  I have experimented with several different hive bottoms and am experimenting to make a hive bottom that will allow mite drop counts without moving hive bottom.  However, I must admit that my years of bee keeping to not compare with those who have been doing this for years.  The thing that amazed my neighbor, who has kept bees for more than 50 years is how many bees were in my hives - and being in the Southern USA, that they never had a beard!  He puts additional covers over his hives (plywood painted white) to keep his bees from all hanging out!  

As to productivity - I just know that I have more honey than we need, and find it to be a great way to give gifts to those who have everything.  Except honey from my sons hives.  Cannot compare to my neighbor's hives - has different bees(more aggressive) and wooden frames with foundation.  I bought a queen  from him for one of my hives that went queen-less after split(I am still learning) and will learn how to replace a productive queen this spring as I don't like to be stung!  

He likes the design of the hive and we will try it on his hives next spring.  Will take his most unproductive hive and one of his more productive hives for production experiment.

Best of luck to you in your bee keeping.  

Tim Rich