I prefer Kmart to Walmart anyday, I guess I think of Kmart as the little man nowadays and Walmart as the big bad corporate wolf. So this Kmart is pretty run down and you usually have to navigate around all the shopping carts left in the parking lot, but I think it is worth it. It usually isn't packed like most McAllen stores and you can just piddle around and find what you need.
Unfortunately, they are usually understaffed and you have to wait in a checkout line forever. Personally for me it is worth it since I don't want Walmart to get any more of my money than they already do. So I have just learned to deal.