Ok, let's start.
1. As a music student (musician) I need to have my notebook open so I can write while playing the piano or in the other case I need to have my notebook open so I can read the notes I wrote while playing the piano.
I achieved to make the notebook stayed open sometimes by putting a small heavy object at one or both sides of the paper so it doesn't close or just by opening forcefully the pages so they stayed open for some time.
In this case this product really fails 5/10
2. Good quality, the construction is nice, quality paper and beautiful design.
I love the detail that it has a nice little compartment in the back side where I can place some small documents.
The elastic thingy that helps the notebook stay closed also is a nice detail.
Beautiful design, details, portable (you can take it anywhere): 10/10
3. Is really practical for me that one sheet is ruled and the other side with staff.
I Really like this product but for me is a 5/10. In my case is super important to have the notebook open without complications, forcing the notebook to stay open ended in damaging it.
Just make possible the notebook to stay open and it will be 100000/100000