Right now, the 1-5 ratings I apply to images, and the color labels in tests I've run, aren't visible to Bibble Pro (4 or 5). I've got workarounds involving sorting the images out into directories by rating, but they're a pain, and are easy for me to mess up.
They also don't seem to be visible to Thumbs Plus, my cataloging application of choice.
Fast Picture Viewer Pro, in contrast, implements these features in such a way that they interoperate with Bibble just fine. I've been using PM for a few years now, and this is starting to get to be a Big Deal problem in my workflow.