I love the quality of the supplies so far. I feel it's a good value for the price. The challenge was a great boost to my creativity and to try techniques I haven't used before. The box contained acrylics, which isn't my favourite medium, but it was surprisingly fun to just let loose and see what happens.
Based solely on the content, I would give five stars.
However, the shipping time (EU) is too long - it's over two weeks that I have to tip-toe around instagram and youtube, afraid to accidentally see unboxings/spoilers. Perhaps you should consider shipping on different times so that everyone receives the box roughly on the same day. Also, it's nerve-wrecking to be notified of the shipping, and know it's two weeks before the box arrives - it would be better to be notified when the box is a few days out. And finally, the shipping fee and the fee for the customs process at the destination mount up to about a third of the price of the box, which I can't quite justify in the long run.
This is the only reason why I gave a 3 star rating.
Perhaps you should consider shipping from within the EU, which would make the deliveries faster. The shipping would be cheaper, so I wouldn't mind paying a few euros more for the box, to make up for the import tax you would have to cover.
In short, better quality and content compared to other mystery art boxes I have tried, but the shipping issues and extra costs are ruining the experience.