Pros
Though Citigroup is going through some very significant changes in their business model, the company is still a good place to get your feet wet. Long term we do not know what will happen to the business as the rules are being changed everyday by the government. However, from day one you will be alongside very talented people (in investment banking / securities side at least) and will be dealing with some of the largest money managers, funds etc . Benefits are excellent with 17 vacation days for new employees,paid sick days, personal days, free meals after 6pm, generous 401k matching, tuition reimbursement, and health care.
Cons
You spend half your day emailing back and forth regardless of where you work. This has to do with the immense scope of the company and immense bureaucracy which introduces multitudes of redundant workers, many of whom think they are very important .