Hi there!! I'm currently in the process of moving OUT from Northfield after my first year. I've been to friends' places when they lived in other accommodation e.g East Slope, Lewes Court, Stanmer Court and hopefully I can help out.
1. Stanmer Court looks nice, and it's really close to the train/bus stations. Spacious kitchens. Gets really hot during the summer though. The whole thing is behind a locked gate so it's super private and quiet apart from the noise of vehicles. It's not very social from what I hear, but is a good place for those who go to the city a lot or want somewhere quieter.
2. Lewes Court - a little grotty, but still decent. It looks homey with its carpet and curtains, has an en-suite (if you pick en-suite rooms), and is liveable if you keep it clean albeit hard to decorate. Basically a low-budget Northfield.
3. Northfield - I lived here. It's literally at the end of campus, so it's super quiet apart from the sounds of cows mooing. Spacious kitchens/lounges, Amazon lockers really close by, there's a good social life because something is always happening in Northfield Bar. But it's also a stupidly long walk to classes. Expect aching feet if you want to make the 15-20 minute walk to the Pevensey building. You get your kitchen cleaned weekly, and your en-suite cleaned monthly. Tons of storage space. Personally I wouldn't choose to live in Northfield again, the only reason being how far away it is from everything. If it were closer to the centre of campus I'd pick it again immediately.
4. East Slope - one of my best friends lived here this year. Super spacious kitchens, locked study rooms in the buildings so you have a quiet library-esque space to revise, the doors unlock with a keycard. Tons of storage space all over the place. It has a very sleek grey theme and is the most high-tech and comfy looking accommodation, and has small double beds instead of the usual single. If you can afford the rent for Northfield then you can probably afford East Slope, in which case choose East Slope because it's closer to everything. It's also really close to the Co-op and most class buildings. The only downside is the enormous crazy flight of stairs you have to walk up to get there, OR the enormous slope if you want to walk the long way.
5. I've never been inside Swanborough, and not many people live there, but from what I know it's basically a slightly older version of Northfield which is a lot closer to the centre of campus. The only downside I can really see is that the windows are stained glass at the bottom rather than frosted - so if you want privacy, you have to pull your blind all the way down.