Hi folks!
I do use Color lables since aperture got them. I also searched on AE for how others use them and i found a good article to use at least one color lable as bookmark.
I would like to share my workaround with others, maybe to learn something:

When i discovered the color lables i desided to use them to sign the postproduction steps inside a Project. Bevor i did this with the star-rating but with some time this got unuseful, because I didn´t have a possibility to “rate” the pics Aperture-wirde again! - the criteria to give a certain star-rating as work-step or as rating are quite different - so i was happy to get a new tool! color lables!
A new projekt first gets a prepared projekt-folder (article in this blog - dublicate empty prepared project); all pics appear in an intelligent album witch is searching for pics without a color lable (sadly: when copying the projekt folder the criteria get lost) - this are the pics i didnt work with. then i go through the pics and give the “x” rating for pics witch are not sharp, or something; (the criteria for the intelligent albums have to search for the ratings as well, to hide the “x” rated - and you have to choos to aply all criteria in the dialog box); the next step is to go through the pics again an deside the cropping, and do rotations and so on…maybe making more then one versions - this step is getting the color lable “red” (my lables are named, but my english doesnt allow a good translation ;-); then i do a automatik correction to all pics and then work through the “red” pics (another intelligent album) and correct what i whant to correct in aperture - this pics are getting a orange lable - maybe a pic doesnt get the next lable, because i dont like it anymore…
then the pics who have to be done in photophop or a plugin are done and get a green lable - for finished pics…then all pics witch are finished, but dont need to be done in an external app get the green lable…at the end i get an intelligent album with green labled pics, witch are finished! So it is not absolutely necessary to have a bookmark - just go through a intelligent album and see if there is a pic which needs something to get the next lable…
at the very beginning i give a blue lable to all pics witch have to be merged as panorama or as hdr, to get rid of them in the intelligent albums - they are processed directly to photoshop and the finished pic get a green lable…
there are some lables left, for more steps, but at the moment i dont need them…
then out of the “greens” i make a album to show friend, another for get prints, another for expoert to the www,…
the star ratings (good tips how to choose the criteria in this blog!!) i give aperture wide! so i always can search for the best pics inside all projects, because the criteria are not projekct-based…
Feel free to start a discussion!!
Thanks
Andreas