The Wal-Mart in my town always has clean tanks with rarely a dead fish in them. it does depend on the day and who is in the pet section as to the knowledgable person working there.
I've never bought a fish from Wal-Mart before because the actual LFS
is right down the road with employees who have worked there for years.
I really dont see anything wrong with Wal-mart fish if everything looks good and one does their research on fish before buying. I just preferr to buy from the LFS
here because I know the staff has been there for a long time and actually can answer my questions without having to look it up.
If the wal-mart fish are quarantined for a while before adding to the tank with healthy fish there really shouldn't be a problem.