It's important to note that these Finder folders, and any files in them, are separate from Things' own file-attachment feature. You can, however, place files related to a project in the appropriate Things-Folders-created folder in the Finder, and then drag those files into the specific tasks that project--in Things--to associate files with a particular task.

If you've got recurring projects and tasks, Things Folders can avoid folder-name conflicts (due to Things allowing multiple projects with the same name) by automatically appending the creation date to a folder's name.

There are a couple unexpected features I also appreciated while testing Things Folders. If you drop a file into the Inbox folder in the Finder, Things Folder creates (or updates) a task in Things' Inbox list titled, "Review your Things Folders Inbox (# files)," where # is the number of files in the folder. That task's Notes field contains links to both the Inbox folder and each file within it--click a link to open the file or folder. I found this feature useful for reminding myself to deal with particular files. Similarly, whenever you delete a project in Things, which causes Things Folders to move the Finder folder for the project into the Trash folder, You get a similar Inbox task titled, "Review your Things Folders Trash (# files)."

Finally, Things Folders can use --an OS X that uses an unofficial area of file metadata to store Finder "tags"--to apply Finder tags that mirror your Things tags. If you install OpenMeta, this means you can use Spotlight to find files based on your Things tags. (I didn't test this feature.)

I did experience a couple minor issues with Things Folders. First, the program didn't work until I moved it into my main Applications folder (/Applications). Second, I occasionally found that Things Folders' background process wasn't working; launching and quitting Things Folders itself seemed to jump-start the process.