Hi! I applied to University (Castle) because well, it's a castle. It's beautiful, and old, and just generally my favourite haha! The hall is gorgeous, it's traditional, and I like a bit of history in the place where I'm going to study. It's a good location too, right next to the centre of town.
I'll give a bit more context on the rest of the colleges too, as I've spent some time there on summer schools etc. The ones after Castle that I really like are as follows:
St Chad's: Very pretty, cute and homely, good location. Traditional and historical. It's very small, which doesn't work for everyone, which I know I wouldn't mind, but some do. The gardens are nice. The food can be a bit weird though, apparently it's privately sourced or something like that. Rooms are alright too.
St Mary's: Very pretty, quite like a old fashioned country boarding school. Spacious grounds and a nice view of the Cathedral. Fantastic location for anything taught on the hill. By default, also close to the library. It's the most traditional college on the hill so still has formals etc. However, there's like an 80% chance of sharing a room at some point though because you have to change rooms on a termly basis. College animal is a boar.
Some that I don't like as much, but know a bit about: Grey's: Very convenient for people taught on the hill. Not exactly pretty, but the accommodation is decent enough. Bathrooms are a bit weird. Food is nice, the hall is nice enough too. I think the percentage for sharing rooms is pretty low, still traditional enough to have formals etc. College animal is a Phoenix, which is pretty cool.
Collingwood: Situated behind Grey's, so again, convenient location. Has a reputation for sporty/ party/ sociable people. Very modern. Really not my scene as I think the buildings etc are really ugly, but all the people I've met from there are nice enough. College animal is a stag. If someone dares you to sit on the statue- don't. The antlers have been broken enough times by drunk students and the college WILL make you pay for it!
Van Mildert: On the hill, pretty modern. Not the nicest looking, so that put me off. Dining hall is massive, nice lights. The food is good and formal hall there is quite nice. I don't think it's very traditional so I doubt they wear gowns there. The rooms are okay, I think one block is ensuite, but the room share percentage is low. The shared showers are weird, they're sort of like cupboard cubicles in the middle of each floor. Some are better than others though. They have a huge lake with ducks, that students there are very defensive of, and its quite cute to see the ducks waddling around. Unsurprisingly, the college mascot is a duck, and I swear Ducks are EVERYWHERE in this college.
Hatfield: On the bailey, traditional. Apparently has a nice dining hall and good food. Decent location. Second oldest and looks sort of pretty. However, I really wasn't keen on the rooms. The decor reminded me of a medieval dungeon which was a little creepy, and the ones we went into over the road were no better. I think they were refurbing at the time so I imagine it's better when students are actually living there. Has a horrific reputation of being full of prep-school kids who are bitter about being rejected from oxbridge. While that's not necessarily true, be prepared for every other college to hate you as a joke, and get a lot of jokes on your behalf. It's just banter, but some people really are not up for that.
Josephine Butler: I've never visited this college, but I know a lot of people really like it because it's the only self catered one, and it's fully ensuite single rooms. I believe it's pretty modern too.
St. Aiden's: This is near to Van Mildert and Trevelyn. I don't know much about it but I will say it's probably further away than some of the other colleges and it's at the top of a bunch of steps.
St Cuthbert's: Again I don't know much about it, but I think this is the one where half the accommodation is new and modern, and the other half is old and on the bailey.
Well that's all I know. Hope this helps!