Pulse has more features, but sits atop alsa. So it's not generally one or the other as pulse still needs alsa underneath. I don't have any docs on which is 'better' but a quick search reveals a lot of opinion on the matter. Bear in mind many Linux distros introduced Pulse a little early (Ubuntu [my employer] included). This caused quite a bit of hatred for it, as it was a bit unstable. Now those issues are mostly gone, and it Just Works™.