Honestly, the guys in Apple stores are usually not as knowledgeable as us geeks who read MacRumors all the time 🙂 During my last visit to the Apple store I was able to teach the employee there some OS X tricks (zooming and stuff) and it was totally new to him. Also, they don't seem to know much about hardware and software specifics of the models. The guys there even didn't know that it possible to configure an iMac with trackpad instead of mouse (after I proved it to them, they gave me a free trackpad 😉 ).
Anyway, the Apple store workers are really nice and friendly, but I won't count on them being most knowledgeable Mac people out there. They usually repeat some simple marketing quotes they were apparently told (I was lucky that the two guys I had the pleasure dealing with quickly stopped doing that after they realized I know more about Apple than them).
P.S. If I were in charge at Apple I'd make all sale employes read MacRumors regularly 😉 You can really pick up a trick or two here.