"Merge" folders?

Let's say I have a folder such as "/Users/me/Downloads/vlc/" and another folder on an external drive such as "/Volumes/Shared/Apps/vlc/"
What I want to do is take the files from the first folder, and move (not copy) them to the second folder, throwing away duplicates and renaming them if the same file exists but is not a duplicate.
And then I want to do that again for all of the folders in "/Users/me/Downloads/" moving/merging them with all of the folders in "/Volumes/Shared/Apps/".
I've been using 'rsync' for this, but it always makes me twitchy, like I'm going to accidentally delete all of my files at any moment. So I'd rather use Hazel for it, but I'm not sure how to do it, or even if it can be done.
What I want to do is take the files from the first folder, and move (not copy) them to the second folder, throwing away duplicates and renaming them if the same file exists but is not a duplicate.
And then I want to do that again for all of the folders in "/Users/me/Downloads/" moving/merging them with all of the folders in "/Volumes/Shared/Apps/".
I've been using 'rsync' for this, but it always makes me twitchy, like I'm going to accidentally delete all of my files at any moment. So I'd rather use Hazel for it, but I'm not sure how to do it, or even if it can be done.