It depends entirely on the specific Walmart and the neighborhood where it's located. I've been traveling the US this summer and have stopped at many Walmarts. Some are well stocked, beautifully maintained stores that you waltz into and out of without a care or delay. Some are run like minimum security prisons, with cameras, gates, security and screens to show you you're on camera (mostly in the makeup isles).

Some Walmart are well stocked, spacious and clean. Some are ravaged, dirty and filled with tourists. It's really amazing the variety of quality.