I generally let Mezzmo automatically handle the display names and thumbnails for my music files, but I like to customize the titles and thumbnails for my video files.

I often change the default label and artwork for each of my video files and the library updates almost instantly if I have only my video files in my Mezzmo library. However, adding my music files to the library creates a significant lag upon exiting the properties tab of any file that I change; occasionally, this can take as long as 30 seconds of watching the 'wait' symbol before the new thumbnail and label populate. It's not a huge problem if I'm only adding one or two files/changes, but if I have to add 10 or 20 then it can take a sighificant amount of time sitting and waiting for the library to rewrite itself.

I keep thinking that if it were only rewriting the video library, then this problem would be resolved.