The problem comes when you are using Skype and then something else uses the
sound card at the same time. I am not a Skype user, but I get around quite a
bit and see frequent complaints. Even power users have problems with it.
Many blame Skype and many blame PulseAudio (just because they like to).
Whatever the problem, it has been around for some time. Lucid is the first
version of Ubuntu with PA that I have heard little in the way of problems in
that respect.

With Windows, having different drivers and codecs is not a problem because
it has a registry and you can have multiple instances of dependencies. Linux
presents problems because it does not work this way. VLC has its own codecs,
but it has no problem. But then, it is open source. Developers can look at
the code and make it work on their platform. Skype is closed, so users
should not blame Linux distributions when it does not work.