I've bought two watches from Katsu (Higuchi) because of lower price and great service: it's a gentleman. Very good: feeling, contact, price, deal, invoice,tracking & feed-back. Both watch by EMS, received in France in 5/6 days. Very bad: I don't speak any write japanese and my english is very poor!!
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.