Pros
These folks know exactly what they are doing. They set high standards, and consistently deliver.
Their project expectations and planning is excellent. The top level management folks are extremely smart and have a great sense of vision and planning. If you go to company social events (which are very frequent by the way), it is quite easy to have conversations with upper management people (Partners).
Deloitte's hiring pattern is very consistent. For the young starters, they hire smart, well spoken, and subtly aggressive candidates. They have excellent training and knowledge management. They have a well oiled and empowered HR and Tech Support group. Things get done pretty fast.
Their paid time off program is really great, and pretty straight forward. No messing about.
They have a big social responsibility program that encourages volunteering. It also presents a great opportunity for youngsters to take event organizing responsibilities. This can be very very useful. Once, I volunteered for an event where we painted rooms for an orphanage center. There was a young guy who did the organizing. We were 10-12 people, with 3 senior executives actually doing paintwork. Quite unique.
I have personally seen that Deloitte's top talents tend to start young, spend a 3-4 years, then take a hiatus to pursue a Graduate Degree (typically an MBA). The firm sometimes re-hires these consultants after their MBA with generous financial incentives. They offer much better packages to folks graduating from top universities. Sometimes they can offer huge joining bonuses.
I worked in the IT consulting division.They tend to get top-end projects. On projects, the average age seems pretty low. A lot of 20-somethings, then there are a handful of 30-40 year old people and some senior Management folks.
Beginner salaries can be a bit low. (which is expected. It takes some time to build credibility in the Consulting business)
Overall, a great place to start your professional career. If you pay attention, you will get seasoned very quickly.
Cons
Work-life balance can become poor, especially during tight project timelines (This is expected in the Consulting Business). The employees have a significant amount of "firm-internal" training and knowledge contribution tasks. There are annual goal expectations. It can get tedious if you continuously work on high demand projects.
There is intense competition, especially during targeted promotion/milestone years. There can be some backstabbing. It's part of the experience. It is not as bad as it sounds, and seems manageable.
A lot of times, being young and inexperienced has it's flaws. The company has a simple way of seasoning consultants. They get pushed into high pressure situations, and they learn fast, and quickly start managing their own work. But they tend to be blind towards intricate details, especially in complicated IT product implementations. This has an interesting effect. If someone is able to do the hands-on work, everyone else tries to piggy-back on that person for their actual work. The hands-on guy gets overwhelmed, and others try to use him/her as a key resource.
-- I personally went through a crunch project, and found a number of people "managing expectations" (piggy backing), while a handful of people actually knew the end-to-end solution and did the hands-on work.
This created a lot more work and mental anguish than needed. Because of the expressed pressure, the hands-on guys have a hard time building and growing their reputation and subsequent performance evaluation rating. This also affects the project execution timelines.
IMPORTANT: Make sure you thoroughly read through your employment agreement and understand the implications. In recent years, they have started hiring for specific projects ONLY. This falls under a particular "AMS service line". In this case, if your assigned project gets into a problem, you are exposed to the risk of employment termination.
Their HR and Management are very helpful, and they will try to get you a new project. But there are several constraints like location, your skills, and limited time. I went through this, and it was somewhat unnerving. This was one of the reasons I ended up leaving the company.