I am currently experimenting with it to see if it can improve my workflow.
As a teacher, I have tons of documents, scanned versions of textbooks and worksheets in my dropbox folder which I have classified by subject and level, and previously accessing them meant driving deep into a certain sub-folder to get a file. Then when I needed another file, keep clicking back (or reopen dropbox).
I have spent a bit of time tagging the files which I feel I will need to access on a regular basis. For example, all my math textbooks are tagged "math", "textbook" and "pX", X is the respective grade level. So if I want to quickly access all my math textbooks, I just click on the textbook tag. To see only my grade4 books, add the p4 tag. It's particularly useful when I need to quickly access multiple files within the same finder window, but would otherwise be better off in separate folders.
It also takes a bit of planning to come up with the appropriate tags. You need to really take a bird's eye view of all your content and decide how best you want to filter them. I have restarted twice already by removing and reassigning tags when I added more files and wanted them to share similar parameters.
At the moment, the results seem promising, but the results will only become more apparent when school opens next year and I have a clearer picture of how useful this feature is when I need it to "just work" under time constraints. It also works great with the "open in new tab" option in finder.