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Or are there notable alternatives?

I don’t mind paying for the app.

Used an earlier version for hunting down and deleting duplicate files between my NAS shares and my mac a couple of years ago. Unless the devs have seriously stuffed up, it was simplicity itself to use and was abundantly clear where the duplicates were located so I could delete the unwanted files/preserve the sole remaining copy exactly where I liked.
 
I used the free version a few weeks ago to do some major cleanup of duplicated files before I reconfigured a backup and it worked a treat identifying them. I myself was too cheap to pay for it so I ended up deleting the duplicate files by hand (which was fine for me).
 
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