Pros
An immense brand which opens a lot of doors. Loads of corporate hospitality options which makes it easy to entertain and retain clients. Very relaxed environment and good, fun people to work with. Lack of job titles equals flat opportunity to represent firm and not be pigeon-holed by a set role. Excellent opportunities to run deals at a relatively junior level. Great for the CV.
Cons
Conversely, lack of job titles equals no promotions, so difficult to argue you're doing a job above your pay-grade and get a corresponding bump. Brand loyalty borders on obsession - naff corporate slogans all over the walls and endless internal presentations where misty-eyed tales of client service abound. There are popular and unpopular departments and these are not linked to performance. The former have unlimited budgets and senior buy in, the latter will be largely ignored. Salaries c.25% below market, in part made up by slighter above averages bonuses (25-50% basic) at 'VP' level, but these can fall to zero in a bad year. If you can make it to the very top, they'll give you recurring share options that set you up for life, but this is likely to be a 10+ year slog of being constantly promised 'jam tomorrow'.