When comparing DoubleKiller vs Directory Report, the Slant community recommends Directory Report for most people. In the question“What are the best software tools to find duplicate files?” Directory Report is ranked 14th while DoubleKiller is ranked 18th. The most important reason people chose Directory Report is:
Once duplicates are found you can choose to select certain files based on criteria like when was it created, when was it last modified, size, folders they're in or if the folders they're in contain a particular string.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Tolerates multiple sessions
I often run multiple sessions of DoubleKiller Pro, to find duplicate files among different sets of disks.
Pro Flexible rules for finding duplicate files
The program can find duplicate files based on any combination of size, name, CRC, and byte-for-byte. It's possible to limit search to files matching a specific name or extension pattern (great for limiting search to certain file types) as well as using the same technique to exclude certain results. You can also tell the software to ignore any of combination of read only, hidden or system files as well as files of below or above certain size and archives.
Pro Offers good options for quickly dealing with duplicates
Once duplicates are found you can choose to select certain files based on criteria like when was it created, when was it last modified, size, folders they're in or if the folders they're in contain a particular string.
Pro Reasonable rules for finding both duplicate files and folders
The program can find duplicate files based on any combination of size, name, CRC. It can also compare files byte by byte. Also, it can compare folders (with or without subfolders) based on any combination of size, name, CRC as well as file count.

Pro Gives a clear overview of found duplicates
It shows duplicate items grouped with every second group highlighted.
Cons
Con No byte by byte comparison
While CRC checksums will be enough for most people, an option to check for duplicate files byte by byte would be nice.
[Edit] DoubleKiller does offer that option.
