We have one Petco near us that has great tanks and great employees. They seem to take very good care of the Bettas too. I got D'Argo there.
But, there is another Petco just a few miles away that seriously needs help in the fishkeeping department. They must be going through a bad time right now because I've seen it decline quickly in just the last month - dirty tanks, dirty Betta cups, empty tanks, no plants, ect. When I visited on Sunday they had signs up looking for experienced aquarists.
The Petsmart that is close to my house has a knowledgeable and helpful staff and whenever I am in there they are cleaning the tanks. But, I don't like the way Petsmart keeps their Bettas in the treated blue water because I can't see them very well. But, as far as I know that is company policy and not a reflection on that particular store.