I will put in my two cents- Mac Mall is fine, have used them and had no problems. I would also say PC/Mac connection is great as well. They are a local company for me here in NH and service world wide through catalogs just like Club Mac, Mac Mall, etc. I actually personally know the CEO of Mac/PC connection. She started the company originally, gave up control and then took it back due to some mismanagement over the last few years. She has quickly gotten it back in order from what I hear.
I will also add that most of those catalogs are all owned by one person. I am almost positive that Mac Mall, Mac Zone and Club Mac are all three owned by the same parent company. I know there are two of the major catalogs that are the same company.
good luck with mac Mall.