I bought my 500M online from Vanns. It was delivered within a week via FedEx Freight. I opened it up and inspected the panel before the delivery guy left. Most 500M's were delivered without problems, some were broken on delivery.
The big problem was the 600M's. They initally had something like a 40% damaged in shipment rate or higher. I believe that Pioneer then called back the 600M's and repackaged them.
There is a whole thread at AVS about it.
Here
A couple of people on this board have had theirs delivered with no problems, so I don't think it's much of a problem now. But you better hurry, the stock is quicky disappearing.