Notes sync resembles that of the My Mission - it follows the same approach that all the sync actions are ordered by you, no auto-background note moving/saving that might lead to results not really expected.
When you press the sync button on the Notes page, it will lead you to a 3-paged/tabbed sync page (called Google Notes Sync). Here you can load the notes saved locally (left tab), those saved on google (right tab). The middle tab is used for merging - process of defining what notes have been changed on either side and what should be done with that.
On Google tasks notes are saved under the list 'Notes'. All the tasks under this list accounted as notes. When you press Load on the Google tab on the Google Notes Sync, these notes will be loaded to the tab. You can view any particular note on any tab - click on an item in the list and it will lead you to the Note page.
After loading the google notes (if they exist), you can run the merge - the program will step through all the notes and try to find out which of the notes have been changed.
A note might be in any of the several states: local new - new note on the device, not synced to the google. The action for such note might be - to sync it with google (i.e., copy it there), do nothing or delete it. Similarly, a note might be a new one coming from google. Same set of actions can be used for such note.
A note may be modified after being synced previously. For example, modified on google. In this case you can copy updated note from google to local storage, restore google note with the local version, or do nothing :).
Convenience filters on the top of the page: you can view only those notes that have been changed in any form - press the Updated text button. You can view only those In sync. Or, you can see them All.
Finally, a note may be modified both locally and on web. The app doesn't try to be too smart, so it doesn't really do the merge or anything. It just sygnals you the situation and let's you take the action.
Pressing on the Apply button will do the sync operation - save new local notes to google, update local storage with new items from google.