The major differences are:
* Unrestricted Disk Storage: limited only by capacity of your device.
* Local Passcode Lock: secure local access to your documents.
* Email: send documents as email attachments directly from Files.
* Bookmarks: add bookmarks to documents for quick access to frequently viewed sections.
* Go to Page: quickly jump to any page in a document.
* Image browsing, slideshow and thumbnails: quickly browse images from the viewer, or sit back and enjoy a slideshow, with various transition options.
* Image thumbnails: Files will generate image thumbnails in the file viewer.
* Copy Images: copy images from Files to the Photos application.
* Audio Playlists: automatically play back an entire folder of audio files as a playlist, or move manually between tracks.
* Quick Scroll Bars: quickly jump to a file or page number with Files' quick scroll bars.
* File Name Search: quickly filter files and folders using the handy search tool