I have never had an issue with them. It helps to know something of what you are looking for or an idea of what you are asking.
I have encountered the high school dim-wit clerk who only uses his camera phone for a camera, but the majority are professionals and know their stuff.
They are also not afraid to tell you who else sells it or has what they do not.
They are local, don't need to wait while the UPS guy delivers and they are fun to talk with...