I guess I haven't been paying attention; I'm not familiar with FontFinder or FontExpert.
A brief history?
My business used to be a combination of wholesale jobber of letters and graphics, an aftermarket product named a Scrappy™ Friction Feed Adapter (which added friction feeding capabilities to Gerber 15" plotters of the day), development and publishing of Plotter Art™ vector clip art, and also a type dealer for The Font Company (now defunct).
When we first became a Font Company dealer in 1991 (2,000 high quality digital fonts), we introduced the library into our letter service business. At that point in history, anybody with even 100 fonts was a leader in wholesale vinyl cutting. Most shops did not have their own equipment and a PC or Mac computer controlling a plotter was just beginning to be introduced. Gerber was still the owner of the lion's share of the market and had just introduced its first Graphix Advantage systems.
What happened in our letter business was a daily deluge of faxed orders with samples of an unnamed font and an order "if we had the font". No one really knew how to identify fonts other than having years of experience in dealing with the many styles that were now coming into play.
We found ourselves doing a lot of business but only because I or an employee was spending several hours a day going through printed user guides to find matching typefaces for the orders we had. So in 1993, I hired a programmer and we developed a way to automatically identify type on either a Windows or a Macintosh computer. We named it FontFinder™. It did the job but was lacking in a number of more sophisticated features one would look for today. For example, you still needed to have an array of printed type books to look up what the program would tell you was a match. It was highly accurate though and could, for example, tell the difference between Goudy Regular and Goudy Old Style and could even distinguish between Adobe's version and Bitstream's, Agfa's, Monotype's and URW's.
We brought it to market, got some good reviews and showed it at the NESA 1994 Expo (now ISA) in Washington, D.C. The sales results were decidedly underwhelming and we sold more licenses to the professional forensic document examiner community (who loved it) than we did to the sign and print industries combined ... who yawned and questioned why it should be their job to identify an unknown typeface and not the client's job.
Not too much later, a new product came to market named FontExpert. It addressed many of the shortcomings of FontFinder™ and we became the North American distributors of FontExpert and abandoned any further development of FontFinder™. This time our results were a little better but we lost money promoting it. Digital Art Solutions (formerly Smart Designs) took over distribution and we moved on. I still use FontExpert to this day although it too suffered from a lack of user friendliness. FontExpert disappeared from the market a couple of years ago.
In summary, both products worked very well in the hands of a user who has a good knowledge of type and wanted to save time in identifying unknown fonts but each was less than useful in the hands of a lesser experienced individual. Both products failed commercially outside of the forensic document examiners community while not a day goes by here at Signs 101 without a dozen or so requests for font identification.
That's my history lecture for the day.