When Arch Linux switched to systemd, my laptop (with an HDD) boot times jumped from 11 seconds to over a minute. That 11 seconds was easy to achieve in Arch’s config by removing services from the boot list and marking some of the others as supposed to be started in parallel without blocking others. After the switch to systemd there was no longer a such a simple list in a text file, and systemd if asked for the list would produce such a giant graph that I had no energy to wade through it and improve things.
Later, when I got myself a laptop with an SSD, I discovered that what my older Arch configuration could do on an HDD is what systemd could do only with an SSD.