Good question without an easy answer. I was a long-term Gentoo user but recently dumped it for NixOS. Colleagues were pushing it and so far I'm happy. Much less compiling and manual configuration which is what was driving me crazy about Gentoo. It took rather little effort to get the system in a state that feels very comfortable. But my needs have changed over time too, so this isn't strictly my opinion on what is best.
More than a decade ago a programmer friend got Ubuntu running on a second hand desktop for a rather computer illiterate arts & letters student. He was able to navigate the GUI like any other system, and it had Firefox, OpenOffice, and mplayer. I knew then that Linux is a perfectly fine desktop OS. And now we're back to using Debian of a sort. ;-)
