Pros
Big data; Large; Complex; 3rd Party Systems and custom in-house development. In an IT world, Walmart has it all and at great scale. So if you like variety and complexity, they deliver.
Cons
Leadership is critical to survival and good leadership is very hit and miss, with great leadership rare. There's also no true technology strategy other than fly by the seat of our pants and hope we deliver something! Where stability was never a worry, it seems corporate has lost itself and thus, laid off more people than ever before, causing those left to be very stretch. It's also caused a 'cut-throat' environment as individuals worry about their stability and performance, which created an environment of 'pointing fingers'. The total compensation is quite lacking, given the breadth of responsibility and accountability. You can get much more money at half the stress elsewhere.