I've been here for nearly 2 years, just studied my first year though (foundation, so I'm going into first this year). But student life is pretty good, its a really nice location, night life is pretty good. I enjoy the clubs here, they can be pricey sometimes, but some days are good (trash, big pops, and I'd recommend Donuts at patterns if you're into that, good music and free donuts). The pubs and bars are also chill, there are some really sick places, but they can be pretty pricey. Or if you're more into live music, there is such a big music scene here, you can find gigs everywhere, all kinds of music too.
People are pretty great, I can't really say much on that because I was living with my family this year, so I was quite antisocial. But I have met a lot, and they're all great.
Accommodation in Brighton is generally pretty expensive, if you're in dorms especially, altho its easy to make friends and there are so many house parties. (I lived in dorms for a about 3 months).But I'd say, if you're in private housing, you'd probably want to live closer to the centre. Or if you're at falmer/varley park, they have a free shuttle bus to the centre/the other campuses, so its not too bad, mostly just going home after a night out (they have night buses, but in the winter its freezing)
Can't really comment on sports sorry, but there are societies you can join, definitely go to freshers fair. You don't need to do sports through uni, but its probably better because then you can meet other students.