Some units are less aesthetically challenged than others. In a rural cabin butt ugly is less an issue than avoiding freezing. I've never made any great effort to review all the units available but as I understand it the fireplace type units are generally more about the romance of a fireplace than warmth.

Yes, as noted, there are some models that have blowers that make them pretty good at heating. Unfortunately if the blower doesn't run, you loose power or the blower fails, many of the blowers are afterthoughts and poor quality, you are back to mostly looking pretty. I wouldn't count on that type unit to keep a room above freezing if the weather turns frosty and the power goes out. Might be worth a shot to experiment on a cold day, with the main furnace off, and see if it can keep up without the blower. Better to know while you have power than be disappointed in a blizzard when there are few other options.

Generally the units that put out the most heat, and will continue to provide heat without electrical power, look more like heaters and less like a traditional fireplace. These are convection or radiant units. Confusing the issue, in a nod to the mystique of a fireplace, some heaters offer a small window that allow you to see the flame. These are generally failures as romantic accessories.

What looks like a decent heater for a power-out situation:
http://www.homedepot.com/webapp/wcs/stor...&marketID=1

Edited to add link.