I found this link that shows EPA test results for different models of pellet stoves. I just thought it was interesting how there can be a lot of differences in the amount of pollution emitted by pellet stoves and price does not seem to be a factor. This might be a good guide if you are purchasing a stove as a "greener" way to heat your home.
http://www.epa.gov/Compliance/resources/publications/monitoring/caa/woodstoves/certifiedwood.pdf
http://www.epa.gov/Compliance/resources/publications/monitoring/caa/woodstoves/certifiedwood.pdf