Pros
It's like starting university all over again, meeting a new peer group making new friends etc. There is good professional development although opportunities are not what they once were to move around. If you make good connections with people and learn to "play the game" you can have a pleasant few years. People are very nice, intelligent and you can learn much from them. There is a big emphasis on people development
Cons
Reward bonuses are pathetic for the amount of overtime you do there is a lot of overtime. There are plenty of office politics about and its luck of the draw if you are put on a good job or not and hence how hard you work. The grading system is pathetic and incredibly political. I say this as someone who knew that I was going to leave once qualified and so wasn't too bothered about my grading, however got the same as my peer who worked twice as hard on tougher jobs.