I have ordered from them twice online and once bought things at the museum shop when I visited Amsterdam.
Improvements or suggestions
One of the last items I bought online was placemats that are supposed to reproduce Van Gogh's almond blossoms painting. They are a very poor reproduction and I am probably going to return the items although it is a big hassle since I am in the USA and they are in Amsterdam. They said they will credit my account but I have to pay shipping which is probably more than the cost of the item.