I had both a Duraflame fireplace insert with glass door, and a pellet stove. There are benefits and negatives to each, and everyone should base their decisions on their particular set of circumstances.
- The fireplace insert requires you to have a steady supply of wood, and maintaining the fire throughout the day requires more work than the pellet stove. However, the flame and crackling plus the slight smoky smell when you refuel the insert are things I really enjoy. I clean ash out of the unit about once a season, mostly when it becomes deep enough to interfere with wood addition. Some ash on the floor of the insert is useful because it makes starting fires easier. At night, I'll load 3 pieces of wood and close all vents - in the morning the coals are still glowing, the unit still hot and coals enough to get the fire going again.
- The pellet stove is very user friendly - load the hopper with pellets and you can forget about it for a while - the consumption is quite predictable (I used about a bag a day) so you can easily keep it fired. I never cleaned it much except for shutting it down every moth or so for ash removal.
At one time I had both running (each had the capacity of 2500 square feet), but about 15 years ago I took out the pellet stove and stored it in the garage (where it remains to this day) in hopes of installing it in my shop one of these days. I removed it mainly because I got lazy and installed a heat pump which made it possible to use it as the main heat source. I prefer the fireplace insert for the crackling fire. Even though the pellet stove also has a glass door, it is just not the same, and it is simply a heating unit that takes up lots of floor space while the insert simply sits in the existing fireplace and does not take up any extra space.
The added benefit that I can harvest wood from my property makes running the insert free, so that is also something to consider for anyone thinking about this kind of wood burning appliance. Even if I did not have my own supply of wood, you can go into the national forest and cut free wood in our area. The other consideration is fuel storage - pellet bags take up way less space than cut firewood per season, and a disadvantage of cut firewood is that carpenter ants might try to infest it if you live in an area where those pests are a problem, so one cannot stack wood next to a wooden structure. However, balancing all positives and negatives, the insert came out the winner.
When I had both units in operation, they were my only source of heat.