Everyone who likes Unix-like systems won't install any lennartware on his system. Everything I ever installed which was written by Lennart Poettering does not work. Beware... he also has his fingers in the Fedora distribution.
systemd causes extremely weird behavior of the hardware (simple things like the power switch do not work anymore, cannot shutdown the PC anymore, even after pressing the power switch for 5 seconds! wtf??).
The pulseaudio stuff never worked for me... consequently I install my whole system directly on alsa, because I need sound support and no choking applications. Sometimes you cannot even login, because some desktop environments want to play the start sound.
Avahi is pure shit... networking is even less confusing without it. Avoiding it means: less confusing system. And think about it: actually it comes from "zeroconf" which suggest that everything is easier.
xdg-system is simply annoying. I have never seen any software using such a weird kind of logic: try Gnome/KDE/... start facilities, not supported, then open file with $BROWSER (this isn't even a well-known environment variable), if $BROWSER is not set, use Firefox... wtf??!! When I don't have Firefox... this is bad and when I already open the URI in Firefox it is just worse! xdg is actually doing nothing that is useful.
Please Lennart... use brain when developing applications.