I have only used hardwood pellets, I have looked for softwood or even a blend to try but have not found any locally. My favorite pellet is Hamers Hot Ones. The place I was buying them from changed to something else so they are harder to get. I have been using them on my pellet cookers for close to 7 years, still have about 3 ton. We usually go through 3.5 to 4 a year, heating about 1000 sq ft.
I have always read that soft wood burned hotter, probably due to the resins in it.
when I had the place built I wanted hated floors, the contractor decided I didn't want them and put in an air to air heat pump for my AC and heat with a coil in it. It does not provide a warm heat. The pellet stove provides a much nicer heat, not as nice as a wood or coal stove but far less mess. I actually cleaned mine today to get it ready for when we need it.
what stove are you using? Harman P43 here, put in in 2012, very pleased with mine. I put a combustion fan motor in it last year as it was making noise. I usually get fired up mid November or so and runs constantly until March or April. Only time I shut it off is for a few hours maybe once a month to clean.
Interested in see your ideas on the softwoods. I may need to try to find some, i have not looked for a few years.