Pros
NU has lots of internal resources, good benefits, and for the most part functions like a well oiled machine. Once you're part of NU, and learn how things run, it's easier to find promotion opportunities.
Cons
Some units/offices/departments are prone to inefficiencies, because individuals are stubborn and like to keep things "as they've been". I find NU tends to prefer promoting from within, which can sometimes cause bad habits/patterns to linger.