1. Being a small firm, the success and fulfillment of one's time at Capco depends a LOT on the type of project you get staffed on. The pipeline is pretty small, so one has little flexibility in choosing a type of project he/she wants. It's kind of a "take what you get" culture...so you can either be really miserable (get staffed on a dead end non-consulting staff-augmentation type project that is completely unrelated to your career) or completely content (i.e. getting a project that aligns your career ambitions).
2. Easily one of the biggest cons is the direction Capco has embarked on in the last couple of years - namely targeting more 'staff augmentation' type projects. Although cash cows, these massive projects can hardly be called management consulting projects, and are basically gigantic vacuums that suck up people in bulk, with no respect for their career goals or skill sets.
3. A few people command too much power in ways that they shouldn't. Inevitably, this results in employees having to cozy-up to these individuals in order to advance certain aspects of their career ambitions...particularly when it comes to getting staffed on in-demand projects as well as getting promoted. This does not do justice to the whole "meritocracy" label that Capco prides itself in.