Can't say for other brands but for JDMs the 3 popular Japanese online retailers are very good. Anything wrong with the watch, they will cover your shipping costs back to them. Shipping is fast as well, most of the time, I get my watches in less than 5 days. But the bottom line is still a much cheaper price. The shop in SS2 do give you discounts but is pricing it at double the price of what u pay if u get it direct.
When it comes to Seiko collectors, its not uncommon to have more than 1 watch of the same model, one for wearing and one in the box untouched or even 1 each of the same watch but in different color.