I have found both Davenports and International Magic to be equally helpful and I enjoy visiting both stores.
I was in Davenports last week and the young guy behind the counter was quite enthusiastic and helpful when demonstrating effects and answering questions. I tend to find that once you demonstrate some knowledge of magic, they will open up and talk more frankly with you. I've not had any bad experiences at Davenports (yet) so I guess I've been lucky. The only dowside is that they never seem to have anything I want in stock, which can be frustrating. But I'm always in and out so it's not really a problem. I went in last week for Killer Elite Pro, which they don't stock anymore because, apparently, they "lost the rights to it". Not sure what that means and didn't ask.
I haven't been into IM for a while now, so I must pop in when I next get a chance. I don't know if he still frequents the place, but I used to see Jerry Sadowitz in there a lot. He demonstrated lots of tricks for me in the past and is a very funny, talented guy.
Also, it may or may not interest you to know that the Magic Circle open their doors to the public twice a month for an evening of magic. You get to see the museum, too. I've not been myself, but I intend to at some point.
Details here.