Well, I went ahead with the purchase and I received it yesterday. Shipping was reasonable-Free UPS ground 3-5 days. I ordered a new iMAC 27 inch, which normally retails for $1699. It cost $1607 plus another 3% off through some link which took me to MacMall for a total of $1559.
Everything appeared brand new with all the packaging. The computer looks and works perfectly so far.
I also saved on sales tax by buying online and having it shipped to my home. Macmall has not retail stores in my state so they do not have to charge and collect sales tax. They are based in California, so CA residents would be charged tax. That's how the state tax codes work. I'm a CPA, so I'm fully aware of the tax laws. So total savings were $258 lower than the apple store (again thanks in large part to no sales tax).
If I have a waaranty issue, the computer comes with the same 1 year warranty. I'm not entirely sure if I would have to deal with MacMall or Apple in this event, but I'm crossing my fingers for now.
I read some unfavorable and scary reviews of MacMall, but my experience worked out. I also did verify they are listing as an authorized resller on apple's website.