I just installed a new inside boiler to replace the OWB. I replaced an old inside junker with an OWB but one and a half seasons into it and that was enough for me. I'm rural so smoke and neighbors not an issue. So far I'm real happy with it, I'm using 1/4 to 1/3 the wood to do the same heating. On the + side less wood, only one pump, no water to water HX, back to a pressurized system, domestic water coil internal so one more less HX and associated piping works better to, shaker grates that really work and the ability to burn coal. Also no going out in the rain cold snow etc.to load. ON the minis side unit is inside so more fire hazard, keep the boiler and flu clean has never been a problem before. The mess is inside instead of outside, well a mess is a mess and I would rather sweep up on a concrete floor than rake up a gravel drive. As far as 12 hr burns in the OWB yep just throw in half a truck load in the morning and the other half that night. I'm probably going to make all the OWB people mad and it seems bad to replace a unit less than 2 yrs old, but for me this was a no brainer having lived with both systems. I'll try to sell the OWB to recoup some money but for me its still the best deal and I would not have any problem recommending the Energy King to someone as it works good and is very well built.