When reviewing 2 versions of a PDF in annotation viewer, it can be difficult to see changes that have been made, even in side by side view.
A better scenario would be to have the ability to compare two documents side by side view with differences/changes highlighted.
This would speed up the reviewing process and ultimately speed to market.
Below I have mocked up a scenario, using native Acrobat functionality to compare documents:
Customer support service by UserEcho