This app has been working great for me in general. It has most of what I would need in a PDF viewer and editor, but it lacks in some areas. The viewing portion works great and I love the sync option with Dropbox, iCloud, and google drive. The only part of the app that I would say is lacking a little is the editing part. The editing tools are very basic. There is no compatibility with the Apple Pencil. The highlight option only lets you highlight in bright yellow. The "draw" option does not let you change the line size, or the color. I feel like the app has the basic editing tools, and with a few more additions to what can be done, it would be the most powerful PDF editing tool on the App Store.