A feature that is either missing, or just doesn't work, is a merge function -- The ability to grab any other .cidb file from somewhere else, and add it to yours. One would expect to be able to do this from "Import..." but it doesn't. This is very handy if you have several "users" and can't share the info across log-ins.
Also, in testing this, I found it locks-up consistently in a "can't find" the album information (gives an Okay button which is defaulted, but does nothing when clicked or "entered") whenever I give it several que'd albums to lookup. Kind of useless, since the only way to get rid of the dialog box is to quit, which throws away all the information. BTW, none of the albums presented were without information -- all presented the info when I put the discs in the drive, all over again (but had it do an immediate lookup).

Full Edit, merge, and duplication removal would make this a keeper for sure. Especially since I keep losing my CD Info files to system crashes.