Pros
They invest alot in their employees' training opportunities. There is always an opportunity to learn about other areas of the company or to dig deeper into a topic of interest. P&G also strongly encourages collaboration, so you could really get into anything that they have to offer project-wise (as long as you have something to offer back). I would also mention job stability, but that goes for most large consumer products companies. They make it very clear how you can succeed within the company (by their definitions of success), but it is also possible for you to make your own way to meet your own definition of success as well.
Cons
Upper management is very resistant to change and new technology. Be prepared for your great ideas to be shot down...then adopted 3 years later once upper management can wrap their heads around it. The recruiting process is a mess, their [R&D] recruiting "teams" are people with full-time jobs in technical roles looking to make the numbers. They recruit as a "side job" so alot of people/papers/etc. fall through the cracks. If you aren't careful they will treat you like a commodity. If you do not have an engineering degree- ask SPECIFIC questions about everything. Never settle for the first "fluff" answer that they give you. Be prepared to be under-utilized your first 1-2 months (or more) with this company. They assume it takes a lifetime before you can contribute something of worth. Be persistent and take initiative to get meaningful work up front.