Pros
They will give you a job if you're in desperate need of it. They constantly need new employees to replace the old ones that got sick of putting up with their undignified, dehumanizing, and unethical behaviors.
Cons
Unethical workplace practices - you will work overtime without being properly compensated, they will take away your vacation and sick hours without your consent, you will constantly see a mistake on your paystub regarding the work you put in and the pay you should be receiving, sometimes the pay is delayed for whatever reason, you have no rights as a worker because you are essentially an outsourced form of labor for the airline. I recommend you Google the lawsuit filed against them by Zeinab Salas - a lot of former employees (myself included) got a settlement check because she sued Hallmark for unethical and illegal workplace conduct regarding work hours and proper compensation.