When comparing Xournal++ vs PDF Expert, the Slant community recommends Xournal++ for most people. In the question“What is the best software to annotate a PDF?” Xournal++ is ranked 1st while PDF Expert is ranked 9th. The most important reason people chose Xournal++ is:
Fill shape functionality, shape drawing (line, arrow, circle, rect, spline), shape resizing and rotation.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Advanced PDF annotation tools
Fill shape functionality, shape drawing (line, arrow, circle, rect, spline), shape resizing and rotation.
Pro Supports pen input from devices such as Wacom tablets
Pro LaTeX support (requires a working LaTeX install)
Pro PDF, PNG export
PDF Export (with and without paper style);
PNG Export (with and without transparent background)
Pro Grid and rotation snapping
Pro SUPPORT
Pro Plugins using LUA scripting
Pro Audio recording and playback alongside with handwritten notes
Pro Fast and smooth
It is a software focused on consumption and not in editing PDF (yes, you can accentuate highlight, draw shapes and sign). They managed to build a nice looking efficient product in which they propose to do.
Cons
Con Expensive for what it offers
It is an item that improves aspects of PDF reading (which is free: Preview) but lacks professional features that other similar software has.
Con Missing settings options
Lacks basic settings like anti aliasing level.