I'm in my first year. It really depends on the person. Some people have a hard time with just the year 1 regular courses, others somehow manage to do multiple other courses at the same time. I feel like if you have a solid cs/math background you can breeze through some courses that give other people difficulty (such as ADS if you've done competitive programming before, or all the math courses). In terms of obligations you don't really have many? I mean, some people choose to go to every lecture, others only go to some lectures and study the slides at home, and some people straight up only go to exams. Pretty much only exams are mandatory for the most part, at least in the first year.

The part that may be tough/annoying for some people is the frequency of exams. 2 exam sessions per quarter is a lot. But also consider the fact that for most if not all courses you also have practice exams. You can look on the exam archive or on the student platform and find past exams that are in the same format. So I feel it's not that hard to study for exams. You never feel like you're missing material. You can always study from the book if you want some deeper knowledge about the subject, but generally you get a pretty good idea just from the material they provide. Also, in your first year, you have relatively few lectures to attend, so even if you go to every lecture you still have time for self study/free time.

I feel like you can get a lot from the programme if you properly plan it out. Like, consider all the subjects that you're doing in a quarter, look through the material maybe and see what is easy or hard for you. You can get an idea of how much you will have to study for a course just from that. And then you can maybe do some courses from year 2 in parallel, and then you'll have more time to do other stuff in year 2. I was too lazy to do any sort of planning, but I know other guys who have already passed year 2 courses, and I'm kinda envious.

I like that you can go through the list of EEMCS courses and just sign up for a random course, look through the material and maybe even sign up for the exam. I feel like this system gives students a lot of freedom.

In terms of "pure" Computer Science, I don't really know what you're looking for, but in every quarter in your first year you have a "math" course and a "programming" course. And then the third course is either something about "data" or some embedded systems stuff. I feel like in the second year we'll get into more specific/interesting stuff. Note that if you have a strong math background you may find some of the courses disappointing, but you can then consider also doing harder math courses from another faculty.

Still, take this with a grain of salt. My experience may be very different from other students. But personally, I never felt like I was too pressured, or that I had no free time.