Dunedin is a good student city. The students have one whole part of the city to themselves so it's a big mix of people with similar interests living together. I grew up there but don't live there anymore. My brother goes to Otago Uni. Dunedin itself isn't that exciting. There are beaches and a harbor but the water isn't what most people would consider warm (neither is the weather). The best part about Dunedin is that it's close to Central Otago. It's probably one of the best parts of NZ mostly because there are tonnes of things to do in both the summer and the winter. I'm biased because I grew up in the south island but I do think it is the better of the two. Everyone's really friendly and laid back. There's heaps of things to do and see. I'm not to sure about the music and theater in Dunedin. I know they both exist. Other than that I don't know a whole lot about them. If you have any other questions I can probably answer them.
its a good town, if you find the right elements. There are some awesome hills to trek through...but i hear they plan to cover them in wind turbines which is a plus and a minus really