MASONRY HEATERS; Masonry heaters are famous for giving steady even radiant heat over a long period of time. But they do have some drawbacks. They are very slow to heat up, often requiring a day or more to satisfy the heating needs    required. If the weather warms up they will over heat the space. They normally require a backup system to keep the space comfortable at all times. They do not distribute heat evenly especially in odd shaped area's or in areas with large amounts glass. The refractory surfaces give a high combustion efficiency but after the fire is out the heater continues to lose stored heat up the chimney reducing the heat transfer efficiency.   
STEEL WOOD HEATERS; Steel stoves have the ability to heat a space very quickly and will heat odd or large spaces through convection and radiant heat, and they will adapt to weather changes. The rapid heat up often causes overheating. The new higher efficiency stoves are sensitive to wood types and moisture content.  They cool very rapidly and do not hold much wood.