Some weeks ago I planed to switch from Things to OS X / iOS Reminders. My deal breaker was to transfer my to-dos from Things to Reminders. Since I could not find a build-in solution, I was searching for an AppleScript. It seems that there was also no easy transfer script. So I build my own one.
The script give you a list of your Things projects to choose from. For the chosen project the script will create a new Reminders list with the same name and copy your to-dos to it. If you have to-dos in Things that are not in a project, simply create a new project and move the to-dos to it.