rumored to be on the App Store in the USA for $300, same price as FCPX.
The cost is relative to the amount of time and effort you waste managing your media without a similar tool. We use a digital asset management system for our still limas called Canto Cumulus. Incredibly expensive and weirdly difficult to master (for something so seemingly simple) but it's an enterprise-grade application running on the servers and managing literally hundreds of thousands of images and other digital files. Several of our operations would be helpless without this image database. So I am quite interested in seeing how KeyFlow stands up to the test of the marketplace and how it might help us manage our FCPX resources in a way that resembles ye olde FCP7 Media Manager. recent project of ours consumed more than 200G of server space for the raw video clips. When we were done building the thing, we needed to keep only the best footage and takes (with handles)--less than 18G. We still don't know how to safely reduce the bulk of our libraries so that 200G is still online wasting a ton of very expensive server-grade drive capacity and redundant backups.
Cumulus will handle video files, too, but, since it runs on servers, it stores the full rez clip as an asset but must have access to all kinds of video processing to serve up the clips as previews or to download them in various formats. That's an entirely and hugely different issue than managing still images. You've got to pay much extra for the software modules that handle video.