Pros
What I like best about Deloitte is the people. Overall most people are very laid back and title/longevity is generally not important. Once you build a strong network of colleagues, it is easy to find work and continue working with those whom you enjoy. Also the variety of work done by Deloitte makes it easy to constantly learn and develop on projects. Most senior managers/partners will allow you plenty of facetime with clients even if you are junior staff. I feel that provided you prove your competency you are given as much responsiblity that you can handle. Most of the policies are fairly flexible provided you can find a senior partner to support you.
Cons
The large firm and audit size often impose a lot of overhead and needless processes and procedures to be completed. There is also a lot of politics involved in getting staffed. The staffing managers are responsible for putting a body in a role and does not worry about your skills/capabilities, and career interests. Once you find your "niche" this mostly goes away but if you cannot find a group of people to support and protect you during downtimes in staffing, etc. you will have a hard time getting a good rating and therefore large raises. Also the compensation is below what you would exect at other strategy firms however this was improving prior to the economic crisis.