My house is about 800 sq ft. It heats 1/4 of the house really well, 1/4 ok, and the other half, not so much, simply due to walls/doors.
I spend most of my time in 1/2 of my house that gets the heat. Flannel sheets on the bed, and a ceramic space heater in the bathroom, and I'm good to go.
It's a space heater, for the most part. It will heat the room it's in very well. If you have an open plan, it may do a better job of heating more area. My house is also very poorly insulated, so I'm sure I could do better with it if there were more insulation in here.
I do pay close attention to mine. I'm cleaning it out after every bag of pellets I burn or every day, depending on how often it's burning. Most of the time I don't have it burning 24/7. It actually gets too warm for me at some times, so I have to shut it off for a few hours. Before I'm ready to turn it back on, I clean it out. It's not hard to dump the ashes in an ash bucket and vacuum the cool ash out.
I think any responsible person heating with fire needs to make sure that they're maintaining their equipment. Just in case, I bought a floor protector and extra insurance for the home and contents.
Something leads me to thinking though, that the guy that had one that burned didn't clean it out.
Again, these things aren't for everyone. But for me, it works great. The best thing is, it's portable and I didn't have to poke a hole in the wall. I'll be in this house for another year, so when I move, I can take it with me, use it in the new house if necessary, or put it in the workshop or garage, or give it to a relative. And I'll only be spending about $300 to heat my house next winter!