I have been working at Citibank full-time
Citi is an entrepreneurial environment for those who can influence in a reasonably non-hierarchical company. If you can prove you've got a better way you can test it out!
Lead times for projects can be long--especially when working with IT.
The process took 3+ weeks. I interviewed at Citibank (New York, NY).
The process was quite easy, you apply and then you will get an email for a link to an assessment. Which is great to help filter out candidates right off the bat. Afterwards you get a email regarding pass or fail.