How do rocket stove compare in heating and efficiency with an ultra low emissions burner

I'm wondering if anyone has experience with the commercial ultra low emissions wood burners ( ULEB ).  They produce something like < 0.2 g/kg of particulates, and like rocket stoves have a  secondary combustion chamber to incinerate most of the smoke.  However, unlike rocket stoves which I've seen and have a horizontal flame in the first burn chamber, the ULEB stoves have an inverted flame where the second chamber is below the first.  After 15-40 minutes to get the fire going you close a valve which redirects the flame path downwards.  So, it takes much longer than a rocket stove to start combusting the fuel in the smoke.

Here's one made in NZ https://www.masportheating.co.nz/products-1/cromwell-ultra-low-emission-burner

Once in reburn mode it certainly may compare quite well with a Rocket stove

That being said, there are very few applications where a Rocket Stove is ideal for spaceheat. (One of which being a double barrel system to release heat directly into a room either to quickly heat a shop for brief work or to serve as a sauna of sorts)

A Rocket Mass Heater gets fantastic results by coupling Rocket Combustion with immense thermal mass to hold onto the heat produced and release it slowly.

Ah, my mistake.  I should have said rocket mass heater.  Are there any emissions data available for the common designs?  There are some cities here where you are restricted to using ULEBs or pellet fires because of the local environment  (inversion layer over the city trapping pollution ).

Also, I'm trying to understand how the ULEB fires work and what they need to establish the draft.  Is it mainly the rate of combustion in the primary chamber that brings in enough air to push the air up the flue, or is the heat in the flue which establishes the updraft?  If it's the latter, would electrically heating the flue help establish the draft more quickly?