Deloitte is a large professional services firm with many opportunities for young professionals to learn and build their overall marketability. It is a large firm and the opportunities are related to performance and time, so progress can be slow for most people. The pay and benefits are excellent, and the caliber of the colleagues is very high. A top performer elsewhere is average here, so expect very high standards.
The pace is pretty grueling, so go in with both eyes open that you will probably work 60-80 hours per week on average, and more during peak times. And not all of this is client work. There will be quite a bit of practice development work like proposals, white papers, recruiting, training sessions, etc. on top of 45 hrs per week of client work.