I use Dropbox a lot, and generally like their mobile apps.
There is one feature of the apps that I love, but it is a bit hidden: the ability to search for files in the Dropbox app by name.
I made a little video to show how it works. While the video shows the iPhone app, the same concept applies to the Android app as well.
This video on searching for files in the Dropbox app is part of a series of quick videos on paperless tips and topics. View more in the series here.