Rated 4 out of 5 stars

well, performed some css experiments... and changed the background to an image as well as made folders animated gifs. Also, I also had changed the top (navigation) bar's color. Any styling necessary is doable, all this addon needs is to add the options to the UI. Also, with different folders having different backgrounds, as well as possibly different folder images, it is apparent that each folder has a unique id (integer), so through scripting (maybe javascript/jquery), css styles can be conditional based on folder ID. anyway... here's a simple snapshot of my ViewMarks so far....
http://picasaweb.google.com/lh/photo/YKD3_flxRYfJYWuquMC4Dg?feat=directlink

This review is for a previous version of the add-on (0.9.5.1-signed.1-signed).  This user has other reviews of this add-on.