Ben Brooks, in our latest review on The Sweet Setup:
We slogged through seventeen different PDF apps to try and find the one PDF app that would change your life — well, at least change your iPad usage. And the best PDF app for managing, editing, and reading PDFs on your iPad is PDF Expert 5 by Readdle. PDF Expert is delightful and easy to use, it offers the fastest PDF reading experience, it works with many syncing services, and it has the most robust toolset available on the iPad.
PDF Expert is a truly fantastic app, and is a great example of how the iPad can take certain tasks which can be cumbersome or complicated on a Mac and make them easier on a touchscreen device. For example, want to merge two PDF documents into one? Just tap, hold, move, and drop — it takes 3 seconds.