Stir the Fire
So far, a couple of opinions that need to edited into a final opinion.
Agitators disrupt the burning process, causing less percentage of the corn to be burned. The act of stirring interrupts the gasification process, introduces cooler temperatures into the pile and pushes more ash, and ash like product into the air where some sticks to the walls of the burn chamber and some exits the stove through the vent pipe.
I was under the impression that the agitators do just the opposite; by stirring up the corn they intoduce more oxygen for a more complete combustion. I suspect the bottom line here to be that some agitators work better than others, and that some non agitator stoves work better than some agitator stoves.
An agitator stove means one does not have to remove the clinker biscuit formed from the corn ash. Maybe more fine ash then ends up in the ash bin. I don't know which is ultimately easier; removing a clinker or emptying an ash bin.
An Agitator type stove can run unattended for 3-5 days before the ash pan should be emptied. There is daily maintenance involved tapping down the fly ash inside the burn area and cleaning off the glass if you feel it necessary to do so.
The Klinker type stove needs the biscuit removed once to twice daily. Although a much cleaner burning stove, forget about going away for a weekend. You have to tend to this daily/bidaily ritual. The only exception is the Bixby stove which empties it's own biscuit, and does nearly everything else except fill itself with fuel. Expect to pay for that convenience if you purchase it with the factory 7 year warranty. Discount new Bixby stoves have been available from dealers and even from Ebay at very competitive prices.
I do know my Harmon does a wonderful job of stirring the corn,and preventing a clinker. It seems to use the same amount of corn as the other stoves talked about here, and it gives off plenty of heat, 45k btu. (pc-45 model)