Pros
Being in a good group is the key to your happiness at State Street. There are going to be groups where the bosses suck and there are going to be groups where the bosses are awesome. I've been lucky to work in a group where the bosses are awesome, they care about the employees and there is room for growth (if you're good). I've been working here for a little less than 5 years and I started not knowing a thing about the financial world. I gained a lot of experience and about 1.5 years later I was promoted to Associate II. About 2.5 years after that I was promoted to Senior Associate. Some of it was luck (I got the position after an employee left), but I was choosen over more senior people for the position. If you are smart and have good bosses you can do well here.
Cons
Corporate bureaucracy - It's hard for big decisions to be made efficiently. Internal Support Groups - They are sometimes slow to get back to you on issues.