Pros
Experience managing and training teams of 5 to 50 people at once. Good health benefits for me (not my spouse). Every day you are put in charge of millions of dollars of equipment and personnel. A chance to learn how to run an operation efficiently. Lateral movement easily available. Ability to relocate to pretty much anywhere. Company has alot of upward mobility at the moment (2018). Stress leave is available once promoted to Full Time status.
Cons
Toxic atmosphere. The normal attitude is to look out for yourself first and only. I am underpaid for the work and responsibility I hold. My benefits do not extend to spouse, they pay full price. As a part time I work 40+ hours a week 3/4 of the year and 27.5 hours for the other 1/4. Full timers often work 60+ and get subjected to a very stress full, performance driven corporate hierarchy. Full timers are subject to mandatory local relocation and assignment to a completely different department. UPS is hard on your body and will wear you down even in a management position. Safety is too often secondary to performance.