Bristol Law grad here so I might be biased but I'd pick Bristol if you are looking further than uni and at careers. From a city law firm perspective - Bristol grads have one of the highest representations at leading US and magic circle firms other than Oxbridge, and the London trio (LSE, UCL, Kings).
As a former committee member with full visbility on the club and its sponsorships with law firms when i was there, I second what Rover5 said about the Law Club and that there is strong alumni to tap into.
In terms of lifestyle/livability, I'd say Manchester and Bristol are on a higher tier given the size and strong focus on arts and cultur, while Warwick is more disconnected and have heard that uni students go to Birmingham for a night out. DM if you need more input.