Compensation: The compensation is terrible in both monetary terms as well as the way in which it is allocated. The time commitment expected, especially as you progress, does not equal the pay offered - to a nonsensical level. People frequently leave for either much more money or a better work-life balance and higher compensation. An even larger issue is the way in which the compensation program is designed. The difference in pay between the top performer in a class and a bottom performer is often negligible. The motivation to work at 100% evaporates pretty quickly when people realize this. The maximum bonus (read: maximum!) you will receive prior to becoming a director is 20K. Most bonuses range from 8K - 12K, and that's for professionals who have actually been with the firm for a few years.
Management style: Very few Partners and Directors are able to lead a team well - the interpersonal skills are simply not there. Your growth and development depend mainly on your internal drive or, in a few cases, from a Director or Partner who has selected you as a favorite. I've been on both sides of the fence - favorite to non-favorite - and both lead to problems. If you are a favorite, expect an angry peer group as it is completely obvious you are a "chosen" one and, if you are not in this group, you must aggressively seek out the top projects and feedback (ie - spend a lot of time on the political aspect, in addition to the work aspect).
Exit opportunities: If you are looking to stay solely within the boundaries of public or private accounting, some corporate finance roles (ie, FP&A) or within the mid-tier professional services bracket, the exit opportunities are definitely there and the brand carries a ton of weight. You'll be able to get those jobs easily. Outside of these boundaries, however, the difficulty increases exponentially the longer you've stayed. Once you've become an experienced Manager or Director, even a minor career switch is going to be challenging.