Smart Notes is a commercial note-taking utility for the Mac. It is also available for iOS, and after you have purchased the app for both platforms, you can sync your notes via iCloud. For this syncing capability to work, Documents and Data storage has to be enabled in your iCloud system settings.
The application itself is rather simple. It consists of a single window divided into three panes. The one on the left shows all your note categories. By default, you will only see All notes and Uncategorized, but you can access the menus and create new categories to help you sort notes. The middle pane shows all your notes' titles and a preview of the first few words of the notes, and when you select one, it will be displayed on the right pane. There aren't many visualization options. In fact, you can only hide the first pane.
From the menus, you can create new notes, new categories, export the notes to XML, TXT and RTF files, and import notes.
In my opinion, for an application that costs 5 dollars, Smart Notes leaves a bit to be desired in the features department. Also, you need to buy a separate application to be able to use note syncing. Honestly, I don't see a reason to buy this app instead of using something like Evernote.