This review is for 23W 131AH. Biskup's lectures are extremely organized and clearly explain the motivations. He is patient in explaining proof details during lectures and offers an insane amount of office hours. Biskup is a very knowledgeable and interesting person, so you would enjoy his office hour even if you don't have questions prepared beforehand. Additionally, the exams are similar to the homework (even easier), and Biskup's grading is more than very lenient, so the workload will not be too bad compared to other 131AH classes.
My only possible complaint about this class is that we spent weeks on the fundamentals, including building the natural and then building the reals, and the pace was probably a bit slow. However, this class is still amazing and provides an excellent, comprehensive foundation for further real analysis. Don't forget to take the BH because the AH doesn't cover much real analysis.

This review is for math 131AH. Biskup is fucking amazing. The class is really hard. Take it if you want to really learn some analysis.

Professor Biskup really wants his students to learn and be engaged with the material. Analysis is a really difficult class and he is very accommodating of students who need to meet with him outside of class in order to master the content. His tests based off of the homework so if you really understand how each problem on the homeworks work than you will do fine. He puts up notes online for you to go back to refer to which was really helpful. The beginning of the class was a lot of deeper more complex theory than any of the other lectures went into which made it difficult to get help from anyone outside of my lecture which only had like 10 people in it. The textbook was really only used for homeworks and not very helpful for gaining an understanding of any concepts you are confused about so you are pretty much reliant on Biskup's notes and being able to meet with him outside of class. Biskup really wants his students to come out of the class learning something and it is possible to do well in his class, but be prepared to put in A LOT of effort.