1st year was definitely the worst, not sure whether I preferred 2nd or 3rd year. In terms of course content, 3rd was better as we could choose more of what we wanted to study, but there was a lot more pressure.
My third year was my favourite. Even though it was hard work, it was where I felt like I actually knew what I was talking about and could really excel.
I loved final year, the modules were super interesting and I felt like we were getting to do the nitty-gritty of things. I even felt kind of sad when it was my final exam, but maybe that was in part cos I was leaving uni and many good memories...