I've been using unix (ie. only Linux but we'll pretend that counts) for over 15 years now. Not quite the "old" you may think of but old enough.
I gave systemd a try. It actively fought me and I cannot accept that. It has too much of a "my way or the highway" mentality that you just can't fix without major C hacking and recompiling. If you don't like its way of doing things then too bad.
sysvinit scripts may be slower to boot and have fewer automatic/behinds-the-scenes features you want, but I can make any arbitrary change to them with minimal effort. I can run them with line-by-line tracing using "set -x" and find out exactly why it's hanging. I can rescue it with *any* install media even if it doesn't have systemd and '/etc/init.d/servicename start' will actually work.
systemd is fine for desktops run by people who think Firefox is the only app they really need to Surf The Net. sysvinit is designed for people who want control of their systems and want to be able to inspect what it's doing. And I'm sorry, I NEED the latter to do my job properly.