Sorry if this has been covered elsewhere as I'm sure it has. Here goes... I need an app like dropbox that allows highlighting and annotation of PDF's. In my dream world this app would work like Preview on my MacBook Air (highlighting, annotation, bookmarks, notes) and the PDF's I save in the app would sync over iCloud to an iOS app where the highlights/notes etc. are preserved. Does anything like this exist? Basically a dropbox/google drive with ONE extra addition...PDF highlighting. PS. I am only interested in pdf readers that sync between os x and iOS.