Yes exactly both hibernate and safe sleep do the same thing. The difference is that safe sleep is automatic and not normally a selection presented to the user.
I think the automatic method is a better arrangement personally.
You don't know what "no known issues" means. It means that the update doesn't cause any additional known bugs. It is not in any way saying that the operating system is 100% bug free.
For example if they were working on an update to Quicktime, but they weren't yet finished, their changes might cause iMovie or iTunes to crash. This would be a known issue listed for that given build number of the update.
Because unlike OpenGL on Windows, Apple uses OpenGL for system drawing tasks. This means that their implementation has to be stable or you get problems like those listed earlier in the thread. On Windows OpenGL is not used for system tasks, only for specific apps.
Also Apple writes a software fallback for all OpenGL calls so that if the gpu hardware doesn't support the function it can be done on the CPU and not just fail. Also their implementation has to cover the...
I'm fairly certain that all DNS goes through mDNSResponder under Snow Leopard. That would be why you are seeing lots of traffic on port 53.Edit:Yes all DNS does in fact go through mDNSResponder. If you would like to disable the multicast portion you can follow the directions here: http://support.apple.com/kb/HT3789?viewlocale=en_US