Great but some memory issues in my experience

Fantastic interface both for searching and sorting. Only problem was running out RAM when I tried running it on too large of a folder (my home folder, 120gb or so). I was surprised because my Mac is pretty new (rMBP, 8gb RAM, only about a year old). Even got system critical warnings. No lasting problems at all though, to be clear—just force quitting and restarting my computer convinced it that it wasn’t dying anymore. Overall, though, highly recommend the app! Especially for use on smaller folders, where it’s speedy and nice to use.

lvmitch about Duplicate File Cleaner - Find and Delete Your Duplicates