ICLOUD
Sync (and backup) your notes with iCloud
You can now sync and backup your notes with iCloud, which is totally free: Any Mac comes with a free iCloud account (with 5GB). Up to 50GB are usually around 1 dollar, find the current prices here on Apple's website.
Notes Plus can now save your notes into you private iCloud account with just one click: Right-click a root folder (the top folder, not a subfolder) in the left lane, click "Add to iCloud", that's it. On another device, click the "Add remote folder (iCloud)" button in the bottom of the left lane, and chose the one you want. You now have the "same" folder on two different computers, and any change on one will be synced within 1-2 MINUTES to the other (be patient! ;)). In cases of conflicts due to parallel edits, a conflict-resolving screen will show.
Tags, priorities, favorite status, pinned status and even attachments like images will be synced too! Find more sync options and the possibility to remove everything from iCloud inside the middle lane gear icon (settings menu).
TODO: proper explanaition and documentation will follow in the next days!