Because of its political nature, this is a topic that's best not discussed unless you have some very specific questions or observations, and you are already very well informed about the merits and faults of both the systemd project and most of the other pieces of software that provide similar functionality. :)
Agreed. Emphasis on pieces of software, plural.
The main reason that does come up that's not really a non-reason (but, I should note, is hard for me to validate as a dispassionate neutral observer) is a fear that systemd is being rammed down users' throats against their wills, partly by distros deciding "there's no alternative" and partly by systemd incorporating ever more tools.
For example, more recent versions of upower are just a wrapper around logind. Thus to have a laptop sleep when you close the lib, you need to replace your init process.
Do that in any way sound sane?
Sound on linux is a mess. And pulse audio is vastly blamed for it. Complex circonvoluted architecture that overpromised and under delivered..
The guy loves to brag about how he is the messiah of a problem and will fixt it, make galaxy like software that are unstable and leave a mess after his doing saying my job is done, let's work on another project where my genius is needed.
But, after utterly messing up once, notably at the (lack of) design level, he has been entrusted to no overpromise again and make the ultimate revolution for the init process. A lot of coders did not believe in his repentance for the mess in pulse audio : he may be as arrogant as linus torvalds he is as smart and a good coder as rasmus lerdorf.
The PID1 on linux is now known as a solar system of processes with nice chaotic trajectories and astronomers are seriously planning to use systemd alone as a nth body interaction simulator.. unexpected .
I experience about zero problems. Maybe it's because I don't run pulseaudio.
That said, at its core Pulseaudio depends on ALSA for the hardware handling.
Frankly the only useful thing Pulseaudio does it handle inputs and outputs when dealing with multiple sound devices. But then so does JACK.
Everything else, from volume control (hello hearing damage with default settings) to bit rate mangling, is massively superfluous.