What's "interesting", or rather depressing, is that any file is opened with the speed of lightning in dropbox. High-res pictures, pdf:s and doc:s are displayed all in the blink of an eye. So, it's the app, not the files or the iPad. And why, why, why display both folders and sub-folders? Very annoying, as it keeps me from creating the order I want in the desktop version, since multiple sub-folders make it's so hard to find the files on the iPad.