Walmart is a great company to work for and offers many opportunities for advancement.
Pros
The management team is well-trained and very professional. Also, the company is very focused on employee and customer safety, offering safety incentives to keep accident rates very low. It is obvious that the management team genuinely cares about the employees. There is also an abundant amount of opportunities for advancement, and you don't have to be employed for a tediously long amount of time before you are eligible for promotions. My personal employment experience with Walmart was exceptional and, if need be, I would definitely go back.
Cons
Depending on what department you get hired in, the hours can be very inconsistent. Also, as with most chain companies, you are not allowed to ask off for the holidays (though you do get holiday pay!) and they are open year-round so you might be working every holiday. Other than that, there really aren't any other cons.