Pros: Good pay, Good company, Good union. History is on the side of both.
Cons: Promotion from within process is cancerous.
Overall, I enjoyed my time at UPS. I worked in one of the skilled trades positions that was regarded as a protected asset and during most of my time there, I felt like we were compensated well but we were usually treated like possessions by junior management (supervisors).
The biggest issue was (is) the foolish promotion process that insisted on 'promotion from within' as the only source of talent. The failure to look outwards for talent and ideas is slowly killing this historic company. The practice tends to favour and encourage the non-producers from the unionized ranks to join the management team while the producers continue to push the company forward. I once questioned this practice and a senior manager (who had come along years earlier from the 'outside') admitted to me that 'we make money in spite of ourselves'.
I left the company under a cloud, one year after I rebuffed the 'order' to put my letter of intent in for joining management. The resultant investigation saw me 'asked' to return to work by the Teamsters and being paid for lost time. My co-workers that still remain (10 years later) tell me that the responsible supervisory group from that time is totally broken up across Canada and have not been promoted any further. The managers are all gone.
The several people promoted after I left were all upstanding team players and the upper management that is in place is a solid group. It's a shame the senior supervisors have not been removed completely in order to prevent this type of cancer from growing again. Institutional memory is often limited and short.