Make of it What You Can; Get Out if You're Ambitious.
Pros
Depending on the group, you can do a lot of work remotely...hours in the office can be light. This is NOT the case across the board. It's very easy to take on new responsibilities at State St to gain professional experience. If you simply start doing something, it's very rare that someone will get in your way. In leaner times, when layoffs are frequent, this can get harder to do because people are more protective of their responsibilities. 100% match on 5% of your salary for retirement accounts vests instantly - not a bad benefit. Health/Dental/Vision are ok, but the cost for the employee goes up each year. More PTO than most people use, but zero official rollover to the next year. EVERYONE gets 3-5 weeks depending on title and seniority, plus floating holidays, bank holidays, etc.
Cons
It's never been part of State Street's business model to pay to retain talent. If you are ambitious, part of your "compensation" here needs to be experience gained by work that you actively seek out. Even if you get promoted, no internal increase in salary will match what you'd get for even a lateral move outside of the company. The most "successful" employees at State Street maximize their external value, and leave for a huge raise (50-100% is not uncommon). As you climb the ladder, more and more of your bonus is paid in stock that vests over 5 years. If you get to that level, the longer you stay, the harder it is to leave. It is not uncommon for an employee to refuse a promotion because their cash compensation will be less with a higher title. It's a huge company, and experience differs greatly depending on the path of managers between you and the executives. Unfortunately, one weak or unambitious link in the chain can stall the careers of everyone below them.