I will be happy to give you some insight into my opinion.  I have a Ph.D. in Marine Science.  I have a zoology degree from BYU, an MS from a university in California and a Doctorate from a Tier 1 research university in Florida.  After graduating I taught at a liberal arts university in Florida.  I chose that position over a research job in the Florida Department of Natural Resources. 

I do not teach at BYUI, in fact I have never been to Rexberg.  I do know a number of faculty members who work and have worked at BYUI.  Some are/were happy some not.  I know no faculty at BYUI who only taught introductory courses.

I have worked at universities with a significant research component and universities which required research but placed more emphasis on teaching.  I see value in both approaches. If your career goal is to receive tenure and teach at a major research instuition and supervise doctoral students then you will likely need to stairstep your way through a number of institutions. 

Bye the way "mentoring" students is not simply a function of research institutions.