I don't shop Walmart, but it has nothing to do with their labor practices. I just don't care for their stores--they all appear run-down and borderline slum-y. The buildings are old, crumbling, and of outdated styles. The interiors are unkept and cluttered. The parking lots are torn up, poorly-lit, and feel unsafe. The store locations are generally in not-so-safe, not-so-pleasant, "hood"-y areas. And the employees are generally uncooperative and uneducated (both in their jobs, and in general). (Although I will grant that as uncomfortable as I em with their employees, I'm even more uneasy just being around the typical customer base of those stores.) It's not quite as bad as K-Mart in any of these categories--I won't shop there either--but it's close. I'll gladly direct my business to the relatively pleasant experiences I can have at any Target.
Important note--This is based on my experiences at stores in my area, which is the Twin Cities. Which is home of Target. So I honestly don't know if these experiences are representative of Target/Walmart/Kmart stores everywhere, or only those here. I could easily believe that the Targets here are better cared for because the company is taking care of its home base, and that the others aren't as cared for because those companies realize that this is a Target-dominant region, and therefore don't bother investing much in these stores, and that these opinions wouldn't be as strong, or may even be reversed, if I were living elsewhere. But nonetheless, it's definitely representative of the opinions of nearly everyone I know.