I Love this box! As a US customer, I feel that the shipping cost is usually worth it for the exclusive books and high quality items. On occasion I may not enjoy a specific item but they tend to send bookish items that you can use in everyday life. Also, their SE's are to die for! Throughout my time getting them, I think they just keep getting better.
I've only gotten a few boxes from them. I usually get the "book only" option just because I'm picky about merch from any box. They seem to have a good selection of curated items and most seem to be pretty good quality. The boxes I've received, I've enjoyed. Their special edition boxes are always amazing.