I n my experience, when treated like this I would have walked. No matter how good the machine was or any product for that matter. But since its paid for and on its way, I would seriously check the machine over very well. For all you know he may have half-a**ed packed it and damage may occur. He isn't much of a business man if he treats a potential customer his way.
I hope all goes well and let us know how it works out.