I read that Cubase has more advanced MIDI/composition/scoring features than Studio One, but no one really specifies what these features are.
So my question is what is possible in Cubase that is not possible in Studio One in terms of midi editing?
Hi and welcome,
First of all, scouring is not possible in Studio One at all. There is no Score Editor.
In Cubase you have Note Expression, Expression Maps. You have much more MIDI Functions for processing MIDI data, which speeds the workflow up. You can edit MIDI data by using Logical Editor (very simple logical “scripting”). You have lots of options to sync the music with the video, etc.
Welcome to the Cubase family Mikayy 
One of the many reasons I chose Cubase (after coming from Ableton,FL Studio 12 and Propellerhead Reason 4) is the sheer amount of midi editing and other superb features that my previous Daws,didn’t have .
Each version of Cubase has slightly more or less features. This is a very good video,to show you the various versions
I liked Studio one,but it didn’t gel with me as much as Cubase did
I’ve used Studio One and I can say that Cubase is definitely more advanced than Studio One in the categories you’ve mentioned.
The expression map feature in Cubase is unbeatable!