Well, let me first start off by voicing my skepticism regarding this driver, I was sure that it really had little value since their are many solutions for Audio that work well however my skepticism came to an end.
While I was helping someone else with an issue unrelated to audio I found they were using your audio solution for the STAC9220 and unfortunately I was experiencing an issue getting audio working with this same STAC.
While my audio issue is somewhat resolved (meaning I now have sound) I thought I'd grab the source and see what I could do to make it work better if not properly.
Sadly, the source from googlecode svn is only the driver and that driver doesn't work with the prefPane (I deleted the VoodooHDA.settings file, restarted and it still didn't work with the prefPane) so I'd like to get the source for the released beta's if possible so I can work on them on a system that has audio issues rather than report an issue that you can't duplicate in the hopes you can resolve it.
In closing, I'm impressed, it's a nice piece of work with great potential and believe it will make hacintosh life much better resulting in a single solution (except for certain cases - SEE NOTE) that just works.
NOTE: ALC885, some ALC889, some STAC9220 and some STAC9221
does not need any patched files or third party drivers, it will support native vanilla audio by patching DSDT
to provide the correct information and it will report properly in System Preferences and System Profiler.
If you're lucky, some ALC889's report the ALC885 Codec ID and if yours does then you can use the DSDT
solution and enjoy vanilla audio, the same goes for the STAC9220 and STAC9221 but this is dependent on
the correct information being returned to the driver.