Pros
BCG provides terrific training and you learn how to produce a logical, well presented argument for business decision making in a disciplined way - a very useful tool to have at your disposal when/if you move into industry. BCG has a terrific reputation and having experience with BCG (or other top consulting firms) provides instant credibility. If your aim is to get into industry at a senior level, I believe going down the consulting path then moving sideways into industry is arguably better in many cases than climbing the ladder from junior positions within corporate. Most people are friendly and super smart - a great network to be part of. Obviously, many people see consulting as being a terrific long-term career, for others, I think it is a great learning platform. Almost like an MBA in real life. I learnt a huge amount while I was there. Even though i didn't see myself as a career consultant and found some parts of the experience very frustrating, I would highly recommend this experience as a path into business/industry.
Cons
The experience is highly variable depending on which location and in which practice area (industry). In the end, it is a people business and the caliber of partners that lead certain practice areas can have a big impact on your overall experience - including your learning, the quality of the cases you get put on and also your work life balance. For example, the consumer goods practice in greater china has terrific leadership and if you can align yourself to work on those projects, that means you will get to work with strong leaders, will be in an environment where work-life balance is respected, projects are well scoped and so on. This is not always true for all parts of BCG and there are those who have had to work unnecessarily long hours because a project was not well defined from the start. The staffing process is not always transparent - establishing your own reputation within the firm quickly is important to the quality of your experience during your time there. Like any other people business, there is an official staffing process for projects but, in the end, if the senior partners respect you and wants you on their projects, that is what really makes the difference. I think BCG in greater china in general can do a better job in treat consultants and associates with the level of respect that is standard in other parts of the world.