Limited opportunities for career advancement. Great opportunities if you're just starting out, but career development tapers off and plateaus.
The work experience and culture vary a great deal depending on where in the company you work, who your managers are, your role, what your account is, etc. You could end up with a stellar mentor, great skills building experience, or you could become someone's peon.
Limited skills development and training. Company can be extremely stingy on instructional courses, books, training, etc. Your skills will go stale unless you maintain them yourself.
Favoritism in the corporate office (for both people and pet projects)
Core business is legacy systems - hard to develop skills or stay up-to-date if your day-to-day is on systems that are 10+ years old.
Some employees are mediocre
Low salary
