Silent shutter mode on G5

Hi Folks,

Has anyone worked out or found out any solid information on the totally silent shooting mode that the G5 has?

What are the real life downsides to using this method on this particular camera (there must be some else they wouldn't bother with a mechanical shutter in there!).

Assuming you're working within whatever normal shooting parameters that are allowed (yes ... I know I need to RTFM!), has anyone seen evidence that the silent mode degrades the image in any way over the conventional shuttered mode?

TIA

Ga.