I have been running MIK day and night the last few days only to find out it has a fatal flaw given my efforts to move everything to 256kbit AAC files: it doesnt work with AAC files really .. it cannot update the comments and key tags which are the only sensible places to write the key information as updating the file name messes up your iTunes library if you have the files names managed by iTunes. Bummer. On top of that I am not really happy with the entire workflow of how to initially process your collection and then easily processing newly added files. Finally MIK keeps breaking off when it decides that it cannot process a file.
So this puts a big damper on my experimenting with harmonic mixing .. or maybe I should look at rapid evolution one more time. Speaking of ways to better organize your collection, I am also probably going to try and apply the DJ notation eventually. However I will probably wait until I am ready to start doing real mixes which will require properly beat gridding the relevant songs.