Medflyer
A lot of my military (CF) air force colleageus are in the same boat. We have CC-130 and CP-140 pilots who are very afraid to make the scary jump and salary cut to go to mainline. Senior Captains (rank) are making >$90,000 and junior Majors are making $103,000 flying rusted out airframes al over the world and getting shot at ........ but the $37,000 penalty pay for the first 2 years and living in Toronto with a family just sacres the heck out of guys. I guess going from being a senior guy back down to being the most junior guy in a purely seniority-based system just scares these guys.
Don't worry - you are not the only guy who is facing difficult decisions.
Like the other guys said - get the interview and wait for the job offer from Jazz. That costs nothing. Only after that fact will you then have to face the difficult decision.