Propane is the most simplistic... Plug and play... My 14 and 11 year old boys can install it and make it run in an hour...
I've only messed with one PJ kit a buddy of mine has and it took a bit for him to get it right... He picked it up used, so that may have played a little part... But it wasn't even close to how easy the propane on mine was...
the propane thing is cool but going to cost mroe than i am getting the tbi kit for... that is a major part of going with the tbi...