PulseAudio is a useless piece of shit. It's like ALSA with a bunch of stupid complications. How it got to be the standard sound system for so many mainstream distros is a real mystery.
ALSA with dmix produces shitty quality sound. When pulseaudion was introduced in ubuntu 8.04 it was causing all sorts of problems, mainly with sound latency. If you give pulseaudio a try now you'll see all of those latency issues have somehow vanished, plug-in an audio device to your pc and it magically works like in windows, and the sound quality due to some good resampling is just crystal clear as with OSSv4. While OSSv4 has a very good resampler it fails to support the plethora of sound devices that pulseaudio supports.