Pros
Deloitte is a brand and has a great reputation - it is a foot in the door into whatever area you want to specialize in and into career wise.
Cons
Deloitte is a consultancy practice and so naturally this means going out onto client site and projects, however you will not always be given the opportunity as people may get picked over you or resourcing requirements are strained. The opportunity to grow yourself in terms of SME, project management and other career skills is very limited. You are seen as a number and a rate card and that's pretty much it. Once in a while you will find a gem of a manager who will invest time and knowledge into you, but it is very rare. Most of the time when you go onto project you're thrown into tasks without proper explanation or teaching because management want it done as quickly as possible to get the best margins for the client, and a lot of the work is very monotonous and lacks any thinking on your part. Another thing which I know many people have experienced (from assistant manager grade down to associate), is senior staff blaming junior staff for errors so that they're reputation/brand doesn't get tainted, and the junior staff's career can be very negatively impacted. I know people who've moved team because of this, when really senior management actually messed up on project themselves or gave a task that was too complex for junior staff, didn't explain clearly or didn't check the work. There is a lot of bs and internal politics, and they market themselves as being all about team work and creativity but it is completely not true. Most people are out for themselves and their own career, and I've seen many situations where people have been thrown under the bus. You constantly have to watch your back. It's also quite well known that they under-pay, and that they have a high staff turnover rate but they supplement this with new grads just coming in as cannon fodder.