The method used is CCD shuffle, where some movement detection gizmo (unknown method) senses camera or image movement and then shuffles the CCD in a compensating direction. It can be heard shuffling when you half press the shutter if in a quiet place. More tests and images to follow but at the full 200mm equivalent I can reliably manage 1/24 sec shots, but turn the stabilisation off and every shot is hopelessly blurred at that same shutter speed. I'm happy that it works well, but of course slow shutter speeds can lead to introducing subject movement, so some care is needed still. Others report being able to use 1 second exposures hand held at wide angle settings, but that is chancy. If trying that, it would be better to take 3 shots and pick the best one.
When using a tripod it is always advised with all cameras with anti-shake, to turn off the anti-shake. And of course use the 2 second delay timer so the button press vibration has time to die away.
Examples to follow.....