Pluspunten
With Walmart as large as it is, there are tons of pieces you could touch in the business. You have the ability (with a little work/negotiation) to move to different functional areas such as store systems, logistics, infrastructure, eCommerce, etc.
Minpunten
As you move up the Programmer food chain, you end up doing less development and more leading. And the leading is not necessarily with internal folks. You deal with A LOT of contractors and vendors. Managing them is a bit difficult as they have one goal ... staying on the project and extending profit for their contract. There isn't a lot of use of new technology. If there is, you are balancing your knowledge of the old legacy system while introducing the "new" technology. Too many processes and procedures that limit and slow down the ability for developers to push things to production.