A duplicate file finder has to determine what files are duplicate by some criteria.
None work or can work as fast as Everything.
Though there certainly can be speed differences between programs.
No individual DFF does it all.
No individual DFF "is the best".
They will all have features that may or may not be of importance to you, or may or may not work in a way agreeable to you.
Many times you'll end up using various tools (Everything included) in your search for duplicates.
Easy Duplicate Finder
Only the older 2.4 version is free. Fast. Good options, but must do at least a CRC32 check on the files.
(In other words, you cannot find "dups" based on name alone, or name & file size.)
Duplicate & Same Files Searcher
Free, otherwise much the same description as Easy Duplicate Finder. Directory handling is not as good, though the results list is better.
Free & can find "dups" on name alone, or name + size ...
There are many, many others, & many other tools (like MD5 hash tools) that can help.
Just came across this (& have only looked at it briefly & running sandboxed), DiskAnalyzer Pro
Compare its speed in finding name/size or name/date duplicates with that of Duplicate Cleaner. HUGE difference. So one is obviously using a much better algorithm. Perhaps DA is using a MFT for some of it's indexing.