Wow, not sure that I can answer all your questions.  But, lets see, this is an indoor pellet stove it is an insert for a fireplace.  A Harman

http://www.harmanstoves.com/en/Products/Accentra-Pellet-Insert.aspx

As far as cost, we installed this in the house when we moved in two years ago so I can't compare directly.  Our old house in town had NG hot water baseboard.  I loved that heat source and the NG cost about us $275 per month for the 4 months of winter but that was a larger house two story house.  The 4 tons of pellets should heat the house for the same time period for $175-200 per month.  I have a forced hot air system fueled by heating oil, but, I only use it during the times that we are away for a few days.  Other than that, we haven't used it.  We've been in the house two winters and only put 125 gallons of oil in the tank our whole time here.

I was strongly leaning toward a wood stove insert because I love cutting firewood and splitting it by hand (at least now while I'm still young), but my wife wasn't interested in dealing with wood.  I don't blame her and I am very happy with the conveinence of the pellets.

Not sure if I answered everything, but, hope I did!