It's very high. We are not doing anything scientific around it but talk to the users constantly and I can tell you they are very very happy. The phrase "changed my life" is recurrent.
Where I'm going with this is what part of that can be increased and applied to a wider audience?
When you say applying it to a wider audience do you mean (i) to people who are not musicians or (ii) to musicians not in our focus segment ( e.g., people who play less frequently/more casually)
I'd want to talk to the current focus segment in depth, find out what makes them happiest about what they're doing with your product and look for ways to both increase the opportunities for those things and make them more accessible.
Is that making sense?
I think your current focus segment knows there's a rewarding feeling in return for the effort, and maybe group (ii) isn't as aware, or doesn't know how to get there...
Since our initial focused segment is big enough for us to get traction, we are not currently focused on expanding, but we will do so in the future and asking ourselves/our users the questions you suggest seems to be a good idea.