Avantages
You get to work with a great group of people on interesting, high-profile projects. You get a lot of exposure at the highest levels. Most of the leaders are willing to teach you as long as you demonstrate that you want to learn. Weekends and scheduled vacations are generally respected. There may be some weekend work, but it's generally the exception. It's extremely rare that someone would have to cancel a scheduled vacation to cover work responsibilities.
Inconvénients
Depending on the engagement, the work load can be pretty tough. You may find yourself working i-banker hours without the i-banker comp. When they say 100% travel, you should expect that. The standard for most engagements, at least in the beginning, is 5-days per week on the road. Some engagement leaders care much more about the success of the case than providing opportunities for career development. Once you are known to be good at something, you need to push very hard to expand your skillset.