Pros
*I can only speak to corporate side employment* Any "pros" depend heavily on your position in the company (corporate side V contract side, remote V on site, etc). Some people receive good pay, I do not. I have had some great managers during my time, but all have left.
Cons
Constantly going through an integration, meaning you will never be able to better the company or your position/industry in any way. Management does not care about HOW to get things done, they just tell you to do it regardless of the actual feasibility. The company motto "Do the can't be done" is taken way too literally as a directive. Poor leadership at the top is poor leadership on the trickle down. Everyone is afraid for the vast amounts of red tape. HUGE burn out. POOR PAY, especially for non technical/engineering/director level positions. And a huge disparity between pay within teams and geographic locations. If you want more you really have to go after it and hound. NO BACK FILL. This billion dollar company acts like it has no money. Lots of turn over. No real career mobility and no one cares to level you up. Everything is secretive so nothing can be properly done when working between sectors.