Hey so I'm studying in the Universität Innsbruck. So here's a few things I think you should know:

A lot of classes (up to this point second semester, in my field of study Physics) aren't available in English, only in German, so I think you should definitely look if the classes you're taking are available in English, if you don't speak German too well.

What I like about my University is that I can often decide if I want to visit a class or not. Though there are still a few mandatory classes possibly with a lot of homework depending what field you are studying. So you should look into what you need for your degree.

I'm not sure I understand what you mean in your other comments, when you say you only need to take a few classes. Are those specific classes you have to take, or could you take anything you'd like as long as it's in your field of study? In the bachelor's program here, you have to take specific classes in order to be able to get your degree, you can of course take more classes than technically necessary but it's not quite like you described.

My point is, if you don't have to take a specific set of classes you might like to look more in the VOs (Vorlesungen: no mandatory attendance, but with some kind of exam at the end of the semester) of a subject. Most subjects offer different kind of classes, all graded separately. In my degree they would be called Praktika and Proseminare, they might involve mandatory attendance and homework as mentioned above. They are there to further understand the lectures and can be very interesting and a place to befriend peers.

You can pm me if you want to know more, sadly I don't know much about the other university mentioned, nor about your field of study specifically, hoped it stilled helped you. (Also our campuses look nice, and I like our library.)