I just did some testing, and Imager reads PM and NX2 if the TEXT portion of the color label rating is the same. Since I do my labeling in PM, I had not tried to go the other way. It seems NX2 reads Imager color labels ok but PM does not. Can't explain that. Probably has something to do with where the info is written in the file. Also note that PM and NX2 have more color labels available and have more flexibility in changing color/number combinations. Nikon Cafe has a forum for IDimager. Mike Buckley who participates here, is quite active over there and sort of leads the way on IDimager.
Hopefully, Camera Bits will add a catalog feature to PM or come out with a separate application SOON. All the front end work seems to be done, adding metadata, tags, labels, etc. in PM. There is even the find function. Now it's just a matter of reading that info into a database and grouping it. Easy for me to say since I know nothing about programming. If Camera Bits does as good a job on a cataloging program as it has on PM, it will definitely be the way to go. I guess we've sort of drifted off topic so maybe I'd better stop rambling. You might want to check out Nikon Cafe for more on cataloging.
Woodie