Good not great.
I appreciate the mission behind the brand as I am in a continuous chase for non plastic and bio products.
Talking about my preferences: I would have preferred the button to be of a different material than the overall brush and more pushy. The brush head could have had more brushing material and longer as well. Changing from a bamboo toothbrush with longer and more dense brush, I can see how much value that has.
The carrying/self cleaning case could have been a bit smaller and less square (considering that it does not have a battery on its own is a bit too bulky), a bit unfriendly to take on a trip. I prefer to carry the brush and head in the separate paper bag and leave the case home - not so convenient.
Overall I consider it a nice object with great battery life.