Seasoned Linux users will have no trouble installing any of these packages. More casual users will probably get there eventually, but might be deterred from installing trickier software just to try it out. So a few words on our experience of installing them is appropriate.
First of all, LibreOffice Impress is trivial in many cases because it’ll be already installed with many distributions. If you don’t find it on your system, it’s an easy installation from the repository. Calligra Stage is also simple to install from the repositories. Sozi is just a bit more involved because the latest version isn’t in the repositories so you’ll have to download and install a .deb file.