Pros
The people and engineering / manufacturing processes. As long as customers are paying for you directly or selling a lot of the products you are supporting, the middle management and fellow employees are generally good-natured, smart, and honorable. All of my managers were smart people with good integrity. However, there was a lot of turnover with my managers.
Cons
Engineering job security. CM's don't make their own products and have very low margins, so an engineer's employment is entirely dependent on their particular customer's product success with Flex. Should the customer move Flex sites, cancel the product, or move their business to a competitor, your job will be in great jeopardy. Most of the VP's don't understand or know how to sell engineering capability. If a customer leaves, executive leadership won't keep you & your team around for 6 months to find another customer. Too expensive and no margin to pay for the lulls. Like a contract services company, Flex hires and lets go of employees more frequently.