I think you all need to remember that Petco, Petsmart and Walmart are chain stores (many stores all over) and just because one sucks, doesn't mean they all do!
It's just another lfs for you to use or not use and the difference in the stores is directly connected to the quality/knowledge of the people that work there. You can take the greatest lfs anyone can find, fire the staff and replace it with people who don't know what they are doing and in no time that store will suck!
If your Petco sucks...don't go there! Or better yet, why not talk to the people there and give some helpful advice/knowledge to them? The guy at our local Petco now knows how to tell the difference between male and female swordtails because of us, and I've heard him pass that info onto shoppers and other store members now.
So every lil bit of help you give them benefits you as well as other fishkeepers. It's easy to bitch about a place that isn't up to your expectations, but try to correct the problem, not just complain about it!