Pros
Opportunity to work with many different clients and do a large array of different projects. Deloitte has a good knowledge repository (though the search engine isn't good). It was good working with wide variety of people with diverse backgrounds. Usually the more junior the better as they are keen and haven't been thinned out for the corporate psychopath. Client work is usually challenging and you get to learn alot about the client, its industry and so on.
Cons
Lack of recognition, the company is more interested in who you associate with, what lip service is given to eminence and how you manage not to upset the heirarchy. I've worked with a number of partners who will not speak to a Manager because they are beneath them. Work / life balance is an issue and excessive travelling and flight delays are never taken into consideration into how much they upset you or your family.