I went to Petco the other day and a lot of the bettas were dead, especially the babies, and many of them were having seizures of sorts which I notice is common in that store.. I've only been to the petsmart once and they had only a few bettas. Not sure if that was because they had many customers or because of the low survival rate. Walmart is the worst, though. Every time I go there, there's always dead/half dead bettas and some with extremely severe fin rot. They had a pretty orange VT once that had almost no caudal fin... But the last time I went, they had a dead female sitting on the shelf that was encased in a layer of fuzz that was thicker than her body and her fins looked charred. I'm not sure if columnaris can do that or if it was mold, but she had obviously been sitting there dead for quite some time. I went to a LFS one time, and although all they had were male VTs that were either red or blue and were in smaller containers than the ones at petsmart/Petco/Walmart that had no lids, they did look healthier and none were dead or really sick. I didn't see any fin rot, though, but they were still at room temp in itty bitty bowls.
I think the only place I've ever seen with heated containers for the bettas was earl may... They had them in cups that hooked to the inside of a heated guppy tank. Unfortunately, the cups were tiny and there was a guppy that must've jumped into one of the Betta cups because they had no lids. That was so sad to see that Betta and guppy stuffed into that little cup. The Betta looked like he was trying to get away, but he had no place to go :(
I guess there are minor pros to each store but there is also major cons to each store (which is usually just bad care and always too small of containers).
Edit: oh, sorry. I didn't realize this thread was that old 0_0