Personally, I've never had a problem with Wal-Mart automotive. So far, they have always done my work in a timely and professional manner, but I realize that different locations may be different that way.
But I don't think there is a push in their upper level management to motivate all locations in trying to push the customer into things he don't need, like I've seen in other automotive repair chains.
The Wal-Mart here just does what I ask them to do and no more, and if they ever notice something that needs attention, then they casually tell me, without getting in my face and then getting angry when I tell them that I'll wait till some other time to get it fixed.
There are other things I dislike about Wal-Mart, but I have no qualms with their automotive, so far.