Pros
As a consultant, you can expect to be out on site/working on a client project within weeks of joining the company. The level of expectation for your performance is very high from day one. Interacting with consultants from other firms, I was always struck by how much better I seemed at the job than they were. While the company is very selective in its hiring practices - meaning the quality of its employees is very high to start with - the Customer Systems model is largely responsible for taking these already good people and transforming them into the best. You will grow develop your skills and grow fast here, simply because you will have to work on real projects very early on. It is not for the faint-hearted, but the rewards for having that kind of responsibility really couldn't be matched elsewhere. The atmosphere here is professional. There is an image that comes along with being a Customer Systems employee. You will be expected to conduct yourself accordingly. Travelling is a big part of the job. My 8+ years at Customer Systems were spent on the road. I went where the clients were. The schedule wasn't always predictable, and sometimes it was very demanding. You have to be clear that predictability isn't necessarily a hallmark of a consultant's life. I liked it most of the time, though there were times when it was challenging. I wasn't overworked. Even on tough projects my work schedule was standard. The compensation was excellent. Throughout my time there, I could not find a similar role that came close to offering what I earned - I checked regularly. Looking back now, there is no other consulting company I would have preferred to work for. I liked my job. I liked my colleagues. I travelled and got to work on a wide variety of projects on both sides of the Atlantic. Finally, I set myself up for a great career going forward. I am grateful for the experience.
Cons
It's firm that knows exactly what it expects from it's employees. You were expected to look the part (white shirt, tie). It was not a place that had much room for "letting your hair down" and long chats by the watercooler. All this was in line with my expectations after my interview. None of it was unreasonable.