I burn some pine every year. Eastern white pine. Not too pitchy, but I do wear gloves when cutting it. It dries quickly - splits are done in 6 months. In your air tight stove, you'll be able to control the fire rate and keep the overheat issue down. If you don't (or can't) control the draft, it can easily run away from you and overheat your stove, causing metal or door damage. Some on this forum, and a few of my friends, burn pine exclusively. Our far northern neighbours only have ready access to pine or spruce, and it works for them! If it's free, have at it. If you are paying the same for a harder wood, then get the harder wood. Dry density should determine your price per cord. Happy burning!