I just found this old thread and I'd like to say I've been to both and they are both knowledgeable about fish and keep great stores. I keep a 36g bowfront planted and a
10g reef tank right now.
Fish World's stuff is pricier because its a small store with a small customer base sadly. But I would definitely goto them for a straight answer to your needs. Me and the owner had a debate over whether I had brought in a Green Terror Cichlid or a Blue Acara (the only superficial difference was a black spot), which eventually led to him pulling out a huge field guide book and determining the right one, what store owner would be that concerned? And he still remembers me and the exact fish I've sold him to this day.
Fish Store is another great store. I've been told a thing or two on the more "ideal" side by these guys but you can't blame them I mean its a store dedicated to fish, their profit margin is thin enough. They still know a bunch about fish and I still goto them for advice. They have a great saltwater section too.
I've never seen Ich in either stores and I know for a fact that Fish Store has a quarantine tank in their basement. I've also seen them using drip acclimation.