Hi!
I just graduated from Law at Liverpool with a first - feel free to ask me any questions you may have!
As regards, Liverpool is a strange one. It's definitely falling down the league tables - something that worried me as a student - but still benefits from its relatively strong history. A lot of my friends have secured TCs at top law firms, and I know of a few people in my year who got jobs at MC firms.
As for comparing the two cities, it really is chalk and cheese. Liverpool is a brilliant student city if you're into clubbing, and the vibes that come with cities. I absolutely loved living there, as you get the city experience whilst avoiding the chaos that can be found in London. I imagine that Sussex is far quieter, but can't really attest to this.
I would note that Liverpool is one of the only city universities I've visited that feels campus-y, as the buildings are all in one central area (as opposed to, say, Manchester).
I lived in Liverpool during my stay - it is worth noting that all the uni accommodation is being, or has been, renovated. Carnatic and Greenbank (the decades old accommodation) are both being shut down and replaced, and the replacements are as good as you'll find anywhere.