Higuchi is absolutely fantastic and his prices have been lower in comparison to the other two.
One prior inquiry with Chino left a bad taste in my mouth. Not saying they are bad but they do tend to be "snotty" and have the "big city" attitude.
Higuchi seems to have a very relaxed, easy going, demeanor. A true gentleman. I guess since he leaves in a small town far from Tokyo, he has not been taken by the attitude of the Tokyo based dealer above.
I have never bought from Seiya (Sorry he is expensive most of the time) but my few email exchanges with him have been very pleasant. Only instance were I would buy from him is that if Seiya has a watch that the other two can't source.