This is my second year burning so I have not had the chance to burn many different pellets. Last year I burnt one ton of NEWP and one ton of Pennington (post problem batch I guess). Both seemed ok, Pennington's were definetly dirtier with alot more fines in the bag. This year I bought a ton of Eagle Valley and another ton of NEWP. I also picked up a few bags of Lignetics to try. Still finishing up some Pennington's, so I put a meat thermometer in one of the heat exchanger tubes ( I know not very scientific) and let it stabilize. Got about 187-193 degrees. Put in the Lignetics and let it go for an hour. Checked the temp and was very surprised to see the Lignetcs were burning about 170-178. About a full 10 degrees COOLER than the Pennington's. The Lignetics were cleaner and didn't get the glass as dirty but were also not as hot.