It's supposed to be a way of postponing specialisation until you reach consultant level, which means that they stick you wherever they need you. you might not get any say in this and it could be most of your first 2 years so no guarantee of much choice. I met a couple of people who had been on their project for 15months and were going to be kept longer. Having said that, one person (out of about 25 on the internship) got placed on an MCIM project, and a few on ST&T roles. Apparently once you're in it's easier to shape your career path (after your first role) than it used to be.