I agree that it depends on who works at the lfs. I've walked into my Wal-Mart three different times in a two week period. Twice, the tanks looked great, just the bettas were stacked badly (me and my boyfriend fixed that for them) and the other time, everything was a mess. It really depends on who is at the helm. My local petco has a girl that is great with plants and livebearers, but doesn't really know much about other fish, so she chalks common deaths up to "weak fish" rather than finding out if there is something the fish requires that they're not supplying. The other day, I walked in there to find the neon tank full of ripped up, dying, fading neons...I suspect they've got a huge case of NTD on their hands.
I have two hole in the wall LFS nearby. One I've bought cardinal tetras and a couple of bettas from. The cardinals died and the bettas are doing great. In the same tank that the cardinals died in, ten neons from my local Petsmart are thriving. The other LFS is actually pretty good, I just have a problem with the fact that they sell CAE as small tank fish and recommend betta keepers for the bettas. They also have a bad habit of ignoring me when I'm in there, but I'll put up with the poor customer service for higher quality fish.
In my area, it's all very hit or miss. I just keep an eye on what I'm buying and the conditions of the tank its in. I NEVER add the LFS tank water to my own and I'm setting up a nice little quarantine tank that I will probably use from now on for all my fish.