Pros
Above average benefits, health insurance, retirement etc.. It's primary market (pharmacy) is a growth industry so plenty of opportunity to advance if patient and willing. Good job stability as the retail side is subsidized by the pharmacy. So even if the retail portion is loosing money (the majority of Walgreens stores do) you'll still have job security and growth opportunities thanks to the pharmacy.
Cons
This is really like two companies, pharmacy and retail. Pharmacy drives everything, retail is just a necessity to keep the pharmacy competative. With that said, unless you're the store manager the pay on the retail side is terrible. And if ever there was an example of poorly qualified people in management and decision making positions Walgreens retail is it. (I suppose that's to be expected considering the explosive growth the pharmacutical industry has experienced over the last 20+ years) I realize this is only my opinion and is probably more of an exception than the standard but I'm speaking from the experiences I've had working in the 3 stores where I've been employed. (I expect the same is true at CVS)