If you do a quick search on the Regency 5100 burn times, I think you'll find out which manufacturer considers 1 degree more than room temperature still burning...Checked out the BK King and Princess models at a dealer not too far away. Was hoping to get a look at an Ashford 30, but they did not have any on the floor. Was able to play around with a demo version of the auto damper and to look over the stove internals (well, at least what you can see from the firebox). Took a few pictures, but they did not turn out. The King model makes my stove seem almost toy like in comparison. Really like the deep firebox and the front loading would make N/S loading nice. Dealer confirmed the great long burn times but pointed out that one really needs to balance the duration to heating needs. I told him I was heating 2400 sf and he suggested the King over the Princess for this size home (of course he pointed out every home is different). Asked him about customer experiences regarding burn times and he said most used a 12 hour burn cycle during the bulk of winter to get the needed heat but could do 24 hour burns when less heat is needed.
He showed me a Regency stove that he said was built to compete with the King. It is a hybrid version as it has burn tubes in addition to cat. Said it was rated for up to 30 hours vs. the King's 40. Most of the other stoves he had could not come close to burn times. He said one manufacturer's idea of burn time was when the stove body was at least 1 degree warmer than the surrounding air temperature (not sure which stove and did not ask).
What interested me most about the stove was the air supply tubes at the top of the fire box of the Princess. It wasn't at all clear to me how these functioned; would like to understand how they distribute the air between the cat chamber and air wash of the stove. Would love to see an "alien autopsy" of the internals of the stove to see how it all works. For those with King and Ashford models, do they all share the same air distribution internals (two tubes at top of firebox leading from center air intake) as the Princess?