Lion Preview 4 is still too darn unstable for daily use

I was experiencing twice (probably even more) when I encountered problem trying to save SketchBookPro 2010 document and DazStudio 3 document on Mac OSX Lion Developer Preview 4.  The system will refuse me from saving file at any location, and eventually crashes.  I didn't lost anything particularly information because of such stupid crash, but it still piss me off to encounter such a situation.  So from now on I am switching back to the older snow leopard.  (Thanks goodness that OSX support having multiple OS on the same machine.