Pros
Relaxed working atmosphere. Opportunities for working across offices (domestic and international). Plenty of out-of-work hours social activites, often paid (part or full) by company.
Cons
No where near enough training and development for junior consultants. No graduate development programme. Too much focus on staying billable and not enough time on training/coaching/mentoring. Below average pay. Senior management seem too removed from rest of company and workers lower down the "pyramid". Unmotivating bussiness strategy (use of buzz words like "sustainability"; flavour of the month). Seems like business development people are valued more than technical people; delivery of work should be just as important as winning it. Senior staff tend not to listen to the concerns of more junior staff (often too busy).