FontExplorer X no longer runs in demo mode forever, unless you're still using the original pre-release version. Nevertheless, it's still an excellent tool for power users. Unlike with Apple's FontBook app, FE enables you to compare multiple fonts. But there are other, less expensive apps that can do the same, though they have fewer bells and whistles. And, of course, there's the old standby, Suitcase Fusion, which is still an excellent app after all these years and is well maintained, though it costs $20 more than FontExplorer X Pro. I downloaded Charmas and gave it a test drive. It will work with a big "Unregistered" watermark pasted over the Font Book window. It has some useful features, but among those it apparently does not have is a way to expand the window horizontally. And there is no way I could find to increase the font size. Even in full screen mode the window remains small and the font names are tiny, almost illegible. Given how long this app has been available it should be better than this. If you're interested in a low cost font viewer I'd keep looking.