When comparing Adobe Reader vs KDE Okular, the Slant community recommends KDE Okular for most people. In the question“What are the best PDF viewers for Windows?” KDE Okular is ranked 5th while Adobe Reader is ranked 13th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Integrated cloud service
Gives access to a cloud service that allows storage and sharing of PDF files.
Pro Allows comparing two separate PDF files for differences
Reader can compare two versions of a PDF file and highlight differences.
Pro Best in class compatibility with the PDF standard
Since Adobe is the creator of the PDF standard, it stands to reason that Adobe's Acrobat Reader has the best support for it.
Pro Free and open source
Pro Trim margins
Easily trim margins either automatically or manually for easier reading
Pro Featureful
Pro Table selection
Pro Tabbed view option
Pro Supports touch interaction
Cons
Con No Distribution version of the installer
Adobe only provide exe files and do not provide an msi installer for bulk deployment
Con Lack of support
Adobe support openly admitted to not supporting the product and recommend the use of forums.
Con Proprietary / Monopoly
Con Data Breach in 2013
Con Software feels slow and bloated
Con No way to auto-update for standard users - needs admin credentials to update
Con No XFA Adobe Forms support
Cannot fill PDF Forms created with Adobe.
Con Requires many KDE libraries
Con No middle-mouse auto-scrolling
Instead of scrolling automatically when holding down the mouse wheel and dragging, it instead zooms in or out, in contrast with many other programs.
Con Poor HiDPI support
You may have to tinker with QT__SCALE_FACTOR environment variables to get the desired size and not blurry content (this is a bug; see https://bugs.kde.org/show_bug.cgi?id=362856 and https://bugs.archlinux.org/task/54688)
Con No search results overview
You have to navigate to next/previous hit one by one
Con No "fit to page" option under printing settings
You can only print the content as given so, when you receive a bigger or smaller image thant the default of the printer, you will have to edit it first on other editor.
Con Slow scroll
Its new ultra-slow-scroll for PgUp and PgDn makes it unuseable.