Scott,

Besides the factors you mentioned, I think the customer service provided by the dealer is very important (especially on high end items). I usually buy keyboards and related items from George Kay. I always get a very competative price and the customer service (after the sale) he provides is way better than I have experienced with internet dealers and chain stores.

Any time I have a question about how to do something on a keyoard, George will spend the time walking me through the process. He is the only dealer I have dealt with that knows how to operate and use all of the major arranger keyboards. If George does not have the answer, he finds out.
When I had a question and complaint about the fills on a PA1XPro I purchased, within an hour George had me talking to Korg's US product manager about it. If there is a problem with the keyboard, it is resolved imediately.

When I purchase an expensive item, this kind of customer service is important to me.