It really is impossible to say without having seen the store. I've seen some pretty grim small family-owned stores in my day, and some pretty grim chainstores. Also, perfectly reasonable shops of both kinds. I have also seen two stores from the same chain, in the same town, with clearly a totally different approach to selling fish. Haven't seen a perfect shop yet; the nearest I've come is a pet shop in a department store in Sweden...bit far to go for my fish. But one day I am going up to London to see some of the most highly recommended ones.
I think you hit the nail on the head. Why pass judgement on a store where you've never been? Most of my fish in Miami, have been from large chain stores, but I've purchased equally excellent specimens from individually owned LFS. You have to look at the individual fish, the conditions of the shop, the staff, and the price, not the sign on the door. Use your best judgement.
llj