In the case of the Odyssey, they sell at straight MSRP with no required add-ons. I put down a $500 refundable deposit at the beginning of January. I was quoted a March/April delivery for a Green Granite EX. A few weeks ago I decided I wanted the EX/Navi, and went in and talked to them. They had an unspoken for Green Granite EX/Navi due for mid-march delivery, so I put my name on it.
My only problem with Honda North so far, is that I was promised a test drive in their Odyssey loaner (yes they have one to loan out when your Odyssey is being serviced). Despite asking (and being promissed they would call me when the loaner was available) two more times about the test drive since, I still have not been called to set up the test drive.
I own a Honda Accord (great car) which I purchased at Honda Cars of Boston in Everett in 1996. At the time I was working near by that dealer so it was convenient. I haven't checked with any other dealers besides Honda North on the Odyssey, but I would have had no hesitation going back to Honda Cars of Boston if I was still working near by.