Ventajas
I'm honestly struggling to say something beyond "It's a job. They pay you money, usually."
I worked there for a long time and did not get fired, despite a few choice places I could have been. I assume this is because letting me stay on was probably easier than trying to trick somebody new into taking the job.
Desventajas
Ask yourself the following questions, if your answer is "no," you probably wouldn't consider it a negative. If yes, then these are things you should never expect:
Do you like being treated with respect?
Do you like maintaining your dignity?
Do you enjoy lying to clients?
Do you enjoy lying to people on behalf of other people?
Do you enjoy being, constantly, lied to?
Do you enjoy a cowardly managerial staff?
Do you enjoy not receiving any agreeable compensation (whether financial or just nice accolades?)
Did you really like high school and wish you were still in the cliquish environment of high school?
Do you enjoy being thrown under a bus?