Neither of those apps linked has the ability to import a .pdf or chart. That's what's special about knitcompanion.
Keeping track of yarn stash and projects is ok, but Ravelry already fulfills that need and has a mobile presence. I need something that is specific to patterns.
ETA: If you look at the screenshot in the first post you can see how the .pdf has been imported and the chart can be highlighted to show what row you are on. It's really the visual part that's the most important.