I don't mind this seller, their items look Ok so far.
The only major issue I have with Japanese sellers is the smell. The bags usually smell like... mothballs or smoke according to others. Also depending on how the bag has been stored/cared for, there might be some mold residue in the lining, so make sure you ask questions and read the descriptions carefully.
My personal bad experience (thank goodness it was only a one time thing), was a vintage LV bag that smelled like smoke. I read the description and the condition of smell was mentioned, but I didn't realize the extent of it. I think North America as a whole smoke a lot less than people in Asia. In Japan, they're very liberal about it. You can smoke pretty much EVERY WHERE. At home? Have a smoke. At starbucks? Have a smoke. At work? Have a smoke. Even though the Japanese government is trying to intervene and cut down smoking, it doesn't change the fact that if you get a bag that was previously owned by a smoker, they're most likely a heavy smoker. I threw the bag I got in to the washing machine twice, got rid of all the tobacco residue and most (95%) of the smell. I'm not even sure if the smell will completely go away, I will try smelleze next.