I’d find it helpful if the checklist symbol was a more conventional square rather than the circle.
To me they make me think of bullet points - I don’t find it obvious that they can actually be checked off!
The circle also conflicts visually with the ‘on the agenda’ symbol in the note title.
PS Please don’t go down the Asana route of indicating the circle is ‘checkable’ by putting a light tick mark in the circle - it just looks like it’s already been completed!
We feel the round checkmark fits the style of Agenda better, it’s unlikely we’ll change it.
Fair enough, it’s your app! It’s not a big deal to me, just a niggle, and may be it works well for others. Just sharing my feedback.
Hopefully I’ll get used to it!
I for one really like the round checkmarks, being used to the ones in OmniFocus or Apple Reminders. And it fits the aesthetic of the Agenda app.
I would definitely prefer square checkboxes. I’ve been drawing them for years in my notebooks! 
