As a domain investor himself he wants to make money, he isn't an end user. If you want to hold out for an end user, then you'd have a chance of hitting your expected X,XXX. From his point of view, he doesn't want to pay that much. Also, the fact he pretty much doubled his offer with his counter, my guess is he's getting close to the line of what he is willing to pay. He may not be your ideal buyer, IMO@jhm he counter offered at 500, saying he is a domain investor too.
I agree with you, high xxx to low xxxx is where I feel it should go for. I have offered him 1000. I have invested myself $$$ in it. 1000 would be the lowest from my side.
Seems fair?