P&G is not really a company to develop engineering expertise (at least in manufacturing and at the plant level).
Pros
P&G provides a nice salary with opportunities to really grow your salary provided you follow the P&G way. P&G has some good people who really look out for you and provide mentoring opportunities. P&G looks good on your resume for future employment.
Cons
Have to know how to play the P&G game to move up. Results are mostly based on how your 1 up manager views you and assesses your performance. At the plant level, plant managers seem to view you based off of how your 1 up manager and/or plant leadership views you. Also, not much opportunity to solve technical problems with creativity. Often times, you have to follow the P&G way to solve every single problem (which sometimes is overkill and wasteful). If there is any real engineering work to be done, contractors usually take care of it. Manufacturing engineers focus primarily on process reliability (compiling data, eliminating machine stops, etc.) without really diving in too technically (i.e. minimal design work). To top it off, managers working in the plant level are expected to work minimum 50-60 hours/week, so the P&G mentality can become draining (which is why I left).