You have to manage the transfer. If you change the original audio file outside of Melodyne, you have to re-transfer. Also, the UI, while iconic, requires a lot of window management compared to VariAudio's full-screen editor.
Are you editing or polyphonic instruments like guitars and pianos?
VariAudio (for Cubase users only). Melodyne wins for cross-platform flexibility.
VariAudio for speed and quick fixes. Melodyne for deep, focused editing sessions.
In modern Cubase versions, you can use Melodyne as an Extension (ARA2), allowing it to behave almost like a native tool without the old-school "transfer" recording step.