The advantages include:

• Very rapid indexing.
• Unlike Google Desktop it indexes all the files it is supposed to.
• It indexes videos, pictures, emails — all manner of files.
• You can search by folder, filename, keyword contents, extension, class of file etc.
• It uses a special windows hook to instantly detect changed files. It does not need to periodically scan the entire disk to find them.
• It is able to index emails individually.
• It lets you know exactly what file it is working on when indexing.
• It allows complex searches with AND (+), OR, NOT (-), wildcards (*), parentheses, quotes (for exact match of phrase), NEAR.
• It integrates with the Copernic web search engine. The web image search is much better than Google’s. It gives you pictures only of what you ask for.
• When you make a “spelling” mistake in your desktop search, is asks “Did you mean…”, just the way Google does on web searches.
• I am not totally sure of this, but it seems to put priority on getting recently modified files indexed first. This means the index useful right away. This can be useful if you stored a file and can’t recall what you called it or what directory you put it in.
• If you tell it to use a drive with more space for the index files, it does not idiotically start indexing from scratch leaving the old indexes behind to clutter your disk. It moves them.
• You can also use it to rapidly find files anywhere on the disk when you know the name. Just put the name in quotes in the filename box. If you only know part of the name, leave off the quotes.

• It works only in Internet Explorer and Firefox. It does not work in my favourite browser Opera.
• You can’t turn it off completely without uninstalling it. In fact I could not even turn it off to install a new version, and neither could the installer. I had to uninstall.
• If you exit, and restart, it will not index files that were modified or created during the time it was not running. One trick to get around this is to manually temporarily rename a directory tree then rename it back to trigger a reindex.
• It can be useful to monitor the indexing status to see what files it is indexing. If you see it indexing garbage, e.g. browser cache directories, you can add those directories to its list of do-not-index directories.

They also make a web-based search called Copernic Agent that examines a number of other specialised search engines and combines results. Depending on what you are looking for, it consults about a dozen of the search engines in its much larger list. There are three versions of it. The basic one is free. There is a $30.00 USD personal version and a $80.00 USD professional version. Unlike most search engines you download software to use it that works inside Internet Explorer, but not other browsers. It is a full-blown GUI in its own right. Oddly it does not include the excellent image search you can get by using an ordinary browser.