Pros
Deloitte provides good exposure to a wide variety of businesses. I have seen many different business situations, how they run their accounts and been able to get a better understanding of the issues important to them. The best factor though is the name on the resume - working at Deloitte opens a whole lot of doors. The only reason I would suggest someone work there is if they needed a recognisable brand to boost their resume. At the higher levels, conditions are good if you love the work. But at the lower levels, no one really lasts very long - the hours, work demands and selfishness of senior management ruins your time there. But it's great for getting another job.
Cons
Where to start? The hours demanded are per reputation - in busy times, you'll do 80-hour weeks. At my level, you had very little client exposure despite all the great promises. The remuneration is disgraceful - probably 10-15k less than my peers made in other firms. They pay nothing but then expect your performance to improve. They make a lot of promises, but fail to delliver on any of them. Senior management thinks staff are stupid enough to believe it's "an inspiring place to work", "employer of choice for women", etc, etc. The firm is less concerned with staff wellbeing than worried about creating perceptions, that no one in the firm really believes.