Pros
The pros of working at this firm is, you raise your profile as an attorney because they are well known, and you have a lot of resources at your disposal to help your practice. It's a good stepping stone to aid you in finding a better job elsewhere. The benefits are also pretty good.
Cons
The pay is shockingly low for a firm this large, especially considering that they expect you to bill 2100 hours a year. The work environment and morale at the firm are terrible, because the attorneys are underpaid and overworked, and as a result, the firm is a revolving door. The firm only cares about your billable hours, and does not value the professional development of its attorneys. If you do make your billable hours for the year, the bonus they give you is a joke. This is no place to build a career over the long term.