I just passed 1500 miles today on the original 8JP. It works so well, I see no reason to go away from it, even though I have a couple Ultimax's to try here. I was flogging on it today with the Hurricane 290Race tune pass after pass on the groomed trail, then out in the field in 14" of heavy snow at 8900 RPM. Thing is a beastly animal and very little heat, wear or belt dust. Seems to me the 8JP is a fantastic belt.
I don't see how some are having such problems, or feel the need to go to different belts & rollers and every trick of the week.