my boot time to graphic login used to be 18s. With systemd installed it varies between 52 s and 600s. Detailed look, by editing the grub boot line to drop the 'splash' so I can see what is taking so long, reveals that systemd, far from speeding things up by massive paralellization, just does everything all over again, slower by at least a factor of two. If I needed this, I'd go to Windows! The justification for this overload of the iron is that users won't be mature enough to get the updates performed. That babying belongs to MicroSoft! Linux is not to have the 'hood welded shut', so to speak.