I was at BCG for a year and I was never on an official case. That's the part they do not tell you in recruiting sessions. I never met a client. I spent a total of three days at an actual client site, where I was hidden in a windowless office so that the client didn't know it was getting an extra associate "for free".
I came to realize as well that the job isn't about getting the right answer but about basically making your manager happy. Ultimately, because consulting is client services, your boss is happy when the client is happy, and the client, who has his or her own career to manage, cares more about an answer that makes his or her department look good than about the overall health of the company. While I was never "on the front lines" so to speak, I still had slides to make and research to do. I got very frustrated when my slides were continually edited in ways that I felt were more political than data-driven.
Finally, the review process is so opaque. That is ultimately what sours me about the company. They claim to be quite forthright in their reviews. I would disagree. I sought feedback every week from my manager, who gave me nothing but effervescently positive remarks, including telling me that he was going to give me the highest grade available to BCG Associates on my official review. When the final review actually came back, I ended up getting a middling grade along with negative feedback that directly contradicted praise I had received when I was seeking feedback weekly. Further, even though it was my first review of any kind, and even though I had received a middling (read: not low) score, I was fired from the company within a week of receiving that review. I think the whole process was decidedly unfair. I didn't even get a chance to prove myself until I was six months into the job. I did everything in my control to seek feedback and respond to that feedback. I was told not only that I was doing fine but in fact that I was exceeding expectations and that I could expect to receive a very positive review. After being built up to believe I was doing so well, I received an "average" review that apparently wasn't actually average because I was "transitioned out" as a result of that score. I don't know if they hired too many people my year or what else was going on, but I was completely blind sighted by their decision, and, frankly, I think the way it was handled was both shady and unprofessional.