There are numerous long-term expert users and developers of Linux who've spoken against systemd, its design, its behavior, and its developers. Including Linus Torvalds, Alan Cox, Ted T'so, and Patrick Volkerding
(That's the original developer of Linux, the long-time second in command, the lead filesystem developer, and the Slackware distro's maintainer -- the oldest extant linux distro.)
Mark Shuttleworth, Eric Raymond, and Ian Jackson are notable other critics.
For actual arguments against systemd:
http://without-systemd.org/wiki/index.php/Arguments_against_...
https://igurublog.wordpress.com/2014/04/03/tso-and-linus-and...
The laptop vs server divide:
http://www.infoworld.com/article/2837182/linux/back-into-lin...
Bad design and bad attitude. One or the other might be survivable. Both are likely not.
http://www.infoworld.com/article/2608798/data-center/systemd...
Uselessd's observations on misrepresentations by systemd advocates:
http://uselessd.darknedgy.net/ProSystemdAntiSystemd/
Five troubles:
http://www.draketo.de/light/english/top-5-systemd-troubles
LWN on Debian's debates: https://lwn.net/Articles/452865/
Wikipedia on Systemd's controversy: https://en.m.wikipedia.org/wiki/Systemd#History_and_controve...