First you should look at the criteria that any software utility supports.
In this case not only do you want the (overly simple) Date and Time Stamp
option, but also more advance file checking options such as a
'CRC' check and/or the ability to perform a 'Bit by Bit' comparison between
two files.
Also a good checker should allow you to specify 'Source' and 'Destination'
criteria such as for example:
1) All files located on the C: drive (Source) to files located on the D:
drive (destination)
2) Also look for the ability to specify folders and subfolders as opposed to
the entire drive.
Next the displayed results should give you the option to show 'All' files
that 'Match' or only those that have the same name but fail either a 'CRC'
or 'Bit comparison' check. If a file fails 'CRC' or 'Bit comparison' then it
is truly different.
You should also look for the ability to individually delete the file or
files you choose to delete or 'All' the duplicates found.
That said one utility that I have used in the past is: Beyond Compare
http://www.scootersoftware.com/moreinfo.html
JS