Pros
If you can last for a year and a half, you can take four credits per semester tuition free, but that is likely to change in the future. You used to be able to take credits for free from day one. If the course is during the work day, good luck getting your supervisor to give you permission to attend. Each department has a lot of autonomy, so you don't really need to worry as much about spending money on coffee and your department can run things contrary to the rest of the university, if it pleases. You will also be punished (or not punished) departmentally for infractions.
Cons
Undergraduate admissions is a *hit show. If your position interacts with undergraduate admissions, set your goals low to ensure you won't be very disappointed when even those basic expectations aren't met. Human resources is a *hit show. Good luck trying to find written policy about many of the things that are important to you. Some things are there and some things aren't written down. Since departments are so autonomous, less work gets done across the university and you have to battle with getting things done across departmental lines. Be wary of undocumented "certificate courses" from School of Education, which went undocumented by this university's registrar.