I went to Sussex and loved it —and went on to get a PhD from LSE (and work at the BBC). It was many moons ago, but I loved Sussex—and Brighton—and found my fellow students to be more interesting, engaged with the world and curious—and I would say therefore more intelligent—than a lot of those from higher-ranked (whatever that may mean) unis.
From my observation, I would say the same still holds.
I have also taught at two unis in London — one highly ranked, one low. I had particularly interesting conversations with students at the latter.
As an employer, I have always rated people far more by what they have to say about themselves and their life experiences, and how they interact with—and respect others—than where they studied.
Good luck to all of you!