As a graphic designer, one thing I use Evernote for is as a database for visual research that I find online or in magazines. So the ability to tag (and use multiple tags for a given item) is the best part. So if I find something compelling online or in an e-mag, I can dump it into Evernote and tag it for color, type, layout, whatever. Then easily search later if I’m looking for interesting uses of color (etc.)
I suppose with Google Drive, I could just add the descriptors to the document itself, but the nice thing about tags is that it helps me to be consistent. I can see what tags I’ve set up.