Pros
good salary, good benefits and very good social life - a lot of team outings - you can find very good friends there
Cons
Working at Barclays as an IT is extremly boring. The expectations at the interviews are high and only few pass it, so they recruit high skilled professionals and then let them do a work that a high school student would be able to cope with. The Indian support (RTB) teams (both in India or UK) are awful, they hire incompetent juniors - for example for the unix support they hire people who never used the OS. The meritocracy they advertise all the time doesn't really exist. The politics is the only key and if you want good bonuses, you need to be friend with your boss. The chances for being promoted or moved overseas are close to zero.