Pros
A more friendly environment than some other large firms but with comparable compensation. Strong commitment to pro bono work. Great potential for personal growth as long as you are not stepping on the toes of any of the many catty managers. Partners are generally approachable and easy to work with (obviously varies by section and office) Good training opportunities and benefits.
Cons
The firm is pretty much run by a small number of high-level HR managers/ department directors. Some of them are very gossipy and unprofessional. I have heard of several instances of bullying and manipulation from these individuals. Many of the new attorneys and senior staff are hired due to pedigree instead of how well they fit into culture. You often get the feeling that ML is trying to compete with the larger, more highly regarded firms, but always falls short.