Hi David, I have been burning lodgepole pine and occasionally ponderosa pine in both J tubes and batch boxes with no problems for over 5 seasons. Regular
wood stoves are often choked down and burn at a lower temperatures which wouldn't consume all the fuel and end up condensing on the pipes as creosote.
As long as you burn your
rmh hot and unrestricted (which is how they are intended to be operated) and an occasional inspection, you
should have no problems.