It really isn't. I've been running fedora with gnome-shell for 3/4 months on hidpi and most things run fine. The applications I had problems were Chrome, it's solvable with 200% zoom, although the UI remains small and Netbeans, here it's more serious because the UI is more important than on Chrome. Another problem is the impossibility of having different scalings on different displays. Everything else that I've needed runs fine and It it's getting better with each gnome-shell release since 3.10. And anyone can try it before buying a display/laptop just by running the scaling command given on the article. In my opinion/case the sharpness of the fonts/icons/ui outweight the small problems that I've had, but using Netbeans and Chrome aren't mandatory to me.