Vantaggi
If you have a good network, is like working for a startup and you get a lot of flexibility. The company is basically lacking direction and its run locally by people that do not care for global results. This gives people a lot of leaway for getting away with stuff that you may not get away in other large consulting firms. Having said that, expect to deal with a lot of administrative challenges (expensing stuff is a mess!) and not the best kinds of engagements, but definitely a good place to be while you look out for something better. :)
Svantaggi
If you don't work for technology delivery, you're screwed. No one gives a crap about other business units, especially those in the Management / Strategy Consulting fields. The recent merger with Kanbay was an absolute mess, with so many HR issues that I can't begin to describe. They cut benefits, changed the way people got promoted and a lot of other stuff that made 2007 an incredibly messy year. I know a lot of people just gave up and left just because of the poor way they managed this merger. For a company that considers itself an expert in the "change management" field, this was incredibly bad executed.