MATH 3350

McMillan is a new professor at UVA (as of writing this), so the way he teaches may be pretty different from S24 than it may be at the time of reading this review. Disclaimer: I am writing this as a first year that has only taken math classes with McMillan, so I can't really compare him with any other math professors.
For someone that was not a math major, McMillan is a very accommodating professor. For a class like 3350 (fundamentally an elective class), McMillan is pretty generous with his curves, and makes himself very available during and outside of lecture. When taking his class, I felt as if the class was more of a collaborative effort with the students and him to structure and learn the content, and he always asked how we felt about content, if we were lost, etc. It's for this reason that I recommend McMillan because he really is invested in making his students learn the content and learn math conceptually rather than procedurally.
That being said, McMillan wants you to learn math as logical deductions, not as procedures to memorize, and that's a skill that you have to develop while in class. You will have to spend a lot of time sitting down and think about the material. You will be asked to walk through the explanations for derivations, and it is slightly harder than what other professors offer for 3350. If you give it the time it needs, it becomes a bit easier to read the dense material, but you do need to come into lecture doing the readings if you want to know what's actually going on.
I highly recommend McMillan if you don't have all that many hard classes for the semester you take it with him. By the end of the course, I was personally able to actually "read" math, and I found his cordial demeanor really helpful when asking stupid questions about content and the like. However, if you have a busy schedule, you may want to take the course another time, but I would not pass up McMillan just because he is a difficult professor. #tCFS24