I'd stay away from Duraflame, putting one of those in a fireplace is like calling in an airstrike with napalm, I can smell those when anyone in the neighborhood is burning them, like a chemical spill. The best compressed-sawdust fireplace logs I found were sold under the name "Hi Energy" and didn't seem to have the wax or chemicals or whatever it is Duraflame saturates their logs with.
It should be possible to make your own compressed sawdust logs using say a
3" or 4" pipe and some sort of ram, it's just a question of the value you put on the time you'll use to do so.