Perfectly fine product. Walmart's brands are also carried by most of the big box stores, and they aren't going to risk putting really, really substandard nutritional/food product out. Also, as mentioned, most of these companies buy their base products from the same suppliers, so it's a wash.
As with a lot of things, most of the cost is marketing in the supplement world, back in the 90's, it was mentioned that something like 70% of the cost of a supplement is art and design of packaging and marketing.