Before new update comes out - alsa driver needs tweaking of parameter:
SndSys.Driver.ALSA.SoundBufferms
in psclient.cfg
Default value is 20 ms, and with this I can't hear any sound in Planeshift. I need to set it at least to 100 ms (higher values work too).
Generally alsa works a lot better then oss driver.
EDIT:
Hmmm... Alsa is better, but not ideal. Setting the parameter mentioned above to 150 works quite well, but very often psclient gets muted out of sudden. I have reverted alsa driver to svn revision 23869 (before it was converted to "template based SCF") and this one works better for me. Just FYI.