Hey I'm a 4th year biomed student at sheffield Uni. I have loved my time in sheffield and will be super sad to move away. It's a really lovely city. The centre itself doesn't feel huge like london or manchester, but it everything you need for sure. Theres loads of really nice parks and everyone is friendly, and there are loads of other bars and studenty clubs in the centre. Obviously i'm not too familiar with Hallam, but its really close to the train station, and then the collegiate campus is near Eccelsall road, both really nice areas. There are lost of really up and coming areas of sheffield with independent shops/bars/cafes like Kelham island, Eccelsall road, and division street. The music scene is good, with places like the O2 arena, yellow arches and the Leadmill. And I would highly recommend going to varsity events if you ever get the chance, its said Sheffield's varsity is one of the most competitive and the Ice hockey 1's final is apparently the biggest ice hockey match in europe with how many people go to it. One of the things I love most about sheffield too is how close to the peaks we are, its like a 15 min drive or half hour bus and the views are incredible.
Feel free to ask any other questions! I'm sure if you pick sheffield you'll love it!