Pros
Fantastic work culture, lots of team work. Hardpressed to find someone who would not help you out when you need help.
Depending on which department you're in, you may have it really well, with bosses who genuinely care for your personal growth and career advancement.
Exposure to really high-value files and international cases.
Lawyers are given a dinner allowance, it's really useful when a tea lady brings you dinner when you're staying late.
All lawyers are given rooms, so there's privacy. (Some other large law firms have senior associates sitting at cubicles.)
Once you're a senior associate, you're entitled to an international conference allowance, and it really is useful for when you want to attend international conferences and make your own name for yourself.
The firm has a social responsibility unit, and tries to give back to the lesser fortunate. The firm also has multiple other societies and organises plenty of events throughout the year to ensure a great camaraderie amongst staff and lawyers.
Cons
Depending on which department you're in, you may be subject to very long hours, and verbal abuse. Expect to see lesser qualified peers jump ahead based on their personal relationships with partners.
Can be quite an elitist firm.