I don't like it much, but I can live with the Boyer kickback. It doesn't happen unless I don't put enough leg in the kick, and only when cold and the battery is a little low.
What I got from reading the TriSpark related threads on this site is it may not last long on a solid mounted motor like the P11 with both a lot of vibration and heat. Then again it might, but I do not want to try it to find out.
Anyway, I'm not here to poop on TriSpark. I'm derailing the thread a little to get some information related to the later model Boyer.