Do I have recourse if one professor's section has a higher average grade and "easier time" than my course's section? From my observations comparing syllabi, grades, and coursework with a few of my peers, their professor's section of the same class has a significantly lighter work-load, more lenient grading policy, and a higher overall class-average (we're talking a letter-grade higher).

Do I have a case for a legitimate grievance?
I'm certain your university has some sort of student affairs or advising.  That's who you should talk to.

I teach a class that has another section taught by another professor, and we've worked hard to align the workload and grading.  We did so initially at the behest of the department and our own student advising dean.  Both of us found the request perfectly fair.

A few points to consider though:


Are the classes really identical?  It sounds like they are from what you wrote, but be sure.
Has this been a long-time situation?  If it has been, it's possible the department is well aware of the issue and has been unable to bring about change.  In that case there's no harm in adding your voice to it, but temper your expectations.
Is one of the instructors a new professor/post doc/grad student?  It's possible they're new to this and aren't aware that the difference is a problem.
If you're unable to get anything changed it may just be something you have to accept (or change sections) - tenured faculty often get a lot of leeway in how they handle their classes.


Regardless, if you're going to do anything, don't confront the professors until you've spoken with student affairs or advising.  This isn't something you should be putting your own reputation on the line for, and certainly not with anything like a formal grievance.