Hi there,
Well that is an interesting, and potentially impossible-to-answer
question.... here are some thoughts to consider...
1) Very broadly, it can be the case that top-tier schools are more academically challenging/rigorous than lower-tier or less competitive programs. However there are plenty of exceptions even to that! But when you're comparing schools all similarly selective and ranked etc, the difference may not be able to even be discerned along those lines, especially for some of the other reasons I'll mention in this list.
2) Difficulty of the curriculum is quite subjective!!! A course or semester or topic may be exceedingly difficult to one student, and not to another!! So it's really in the 'eye of the beholder' so to speak.... consider variables such as
-each student's background, academic and professional, as well as industry and role
-previous exposure to that subject, or lack there-of
-quantitative background vs more liberal arts (as both types of students will be at b-school)
-format of teaching (case study, lectures, etc)
-whether grades are disclosed; whether specific courses are graded on a curve; and how much that matters to a given student
-time commitment and personal factors that vary among students (for example someone with a family may feel they have less time to commit than someone who is living at b-school on their own etc; just one potential scenario).
2) Even to get ONE person's (still subjective!) view on this, they'd have to go through each of the schools' programs fully in order to best compare.
3) A given student's choices in electives, course work, projects, exchange programs etc can vastly affect how 'rigorous' they feel the program is.
4) There are some schools that have a perception of being 'even more intense' but there are always different experiences based on the list of variables above that can impact that one way or another.
5) Things you can do to attempt to assess further include speaking with LOTS of students about their experiences and perspectives on each school; and checking out blogs and in-depth school guides such as those we release each year,
https://shop.mbamission.com/collections/insider-s-guides.
Good luck on your research and decisions!