Reunion 12 has just been released. According to the program’s web site at http://www.leisterpro.com/doc/v12/newfeatures/newfeatures.php, the new features include:
New Duplicate Check feature. When adding a person, a new window appears showing possible duplicates to the person you’re adding. You can make it as sensitive as you want. Potential duplicates can be reviewed, to help decide whether to link an existing person or continue adding a new person.