Pros
Working at CVS, on the store level at least, can very much go either way. If you find yourself in store with decent management and good coworkers, it has the potential to be a great experience. CVS can offer a flexible schedule, laid back working environment, the opportunity to make wonderful personal connections with both coworkers and a bevy of customers, and if you're interested, you can learn a whole lot about pharmaceuticals.
Cons
The biggest problems you run into at CVS are usually caused by corporate. Initiatives are handed down to the store level, and despite apparently being successful in pilot stores, they frequently just aren't practical. Also, possibly the most discouraging thing about working at CVS is that if/when a customer takes issue with a policy and you stand firm, there will always be someone higher up willing to break the policy and make you look foolish in the name of customer service.