I'm kinda a bug when it comes to burning. I have burned several different kinds of pellets in my new PB 105 boiler. I have witnessed it light several different pellets and just this morning I noticed whith the summersets it took just a bit longer to light (I have the newest style icniter) . when it lit it was with such force that air came out the slot above the observation window(slot that keeps window soot free). seems to me these pellets light just a bit harder. Also my observations of different pellets in my boiler...high quality pellets do burn better...are they worth the extra $$$...jury is out on that