Almost perfect!
I recently bought enough items from Stocubo to build a really long sideboard and a record shelf.
The quality of the boxes are really great, as well as the required platforms they rest on. The construction was a little more fiddly than I expected, but it's still significantly simpler when you compare it to building IKEA furniture.
The reason why I didn't give my purchase a 5 star rating was because of the Aluminum clips I purchased. In my experience, these clips couldn't connect two shelves together without one of the inner felt pads being removed. Since I bought two different clips in my order, I could compare the experience between the plastic and aluminium clips, and I can comfortably say the plastic ones are the way to go.
This is also another minor point of feedback; when you purchase aluminium clips, it wasn't obvious what clips are meant to connect two baseplates together, versus two shelves together. I assumed the clips were all the same dimensions, and I damaged a baseplate because of that. I didn't seriously damage it, but I do expect clearer instructions.
With all that said, I do really support the brand, and I hope my feedback can help their team.