Systemd for sure have some flaws and it's violates unix style/philosophy of :
"...program design that makes programs easy to use and, more important, easy to combine with other programs.".
Most people doesn't like systemd because it's hard to learn (or they won't read man pages) and sometimes systemd is very frustrating to use. Despite all of that, systemd isn't bad clone of launchd. Systemd have nice features that allows you to put some processes in semi jails. Although, I couldn't find one missing feature from launchd in systemd. Nice tag in launchd allows you to set nice value to job/process (Maybe I missed that).
Systemd isn't faster that other init systems. I use distro without systemd. Runit faster at boot time, but that init system lacks some features. So, I have replaced
systemd.timers with fcron. fcron is my favorite periodical command scheduler. That command scheduler have all I need including nice value for a job/process.