"Good low latency behaviour"
"Very accurate latency measurement for playback and recording."
And most importantly:
"PulseAudio is intended to provide lower latency than the software mixers dmix and esd."
("dmix" is ALSA's mixer.)
And I can confirm that this is indeed the case. Actually, I was surprised at this myself, because before trying PA I stayed away from ALSA (I'm normally using OSSv4, which I still do on my main machine). PA has many problems; however, I came to the conclusion that latency was not one of them. Not only that, but it noticeably improves latency.
I guess the "latency issue" of PA is simply something that sticks around from years back, and everyone is repeating this to this day. Another reason might be some Ubuntu brain damage. The developer of PulseAudio ranted about this, mentioning that PulseAudio has a worse reputation than deserved because Ubuntu (the most widely used distro) didn't offer a well configured PA:
Linking to the PulseAudio website as a source is not a good argument...
There should be independent benchmarks and comparisions if PulseAudio is truely lower latency than ALSA.
Linux needs a stupid simple underlying audio API and PulseAudio/ALSA is not it. OSSv4 would be a much better alternative, though it's mixer GUI needs some work and some drivers need to be ported over to it. OSSv4 is also used by the other Unixes, such as the BSDs. ALSA is only used by Linux.
Steam is not needed, I'm actually afraid of all the CS playah corruption. Hopefully the infection is contained within Ubuntu forums.
I think things would be better without PA. But things not working on it is the fault of distros using it, no way around that.
Devs should just use SDL/OpenAL/libao/whatever high-level sound lib, and expect Ubuntu to provide proper configuration for them to work with $UBUNTU_SOUND_SYSTEM.
On multimedia, I disagree about gstreamer, use ffmpeg. But anyway, in that area it's not really a mess, just a question of preferences.