Since roughly 1/4 of the undergrad class is taking a BofM class at any given time they invite professors from a broad swath of departments to teach these classes.
The academic rigor that professors bring from different departments can be wildly different. What an engineering think about the appropriate level of rigor is very different from what a professor from the Spanish department might believe. As a result you get a pretty varied experience.
The key for students is to do a little research on the professor before signing up for the class. Lots of ways to do this including including Rate My Professor and whatever BYU uses when they use when they ask for student feedback at the end of the term