Fair question. The short answer is: the designs are completely different.
We designed mysc. to make it more casual.
Tho having some similar features, mysc. is designed especially for short and segmented content (like shower thoughts or random ideas) we created on mobile devices with (hopefully) a much gentle learning curve. Therefore the main interface looks more chat-like than note-like.
We don't want to be a tool with the most features but a tool that provides most of the features that matter to people's daily life in the most accessible way.