>I'd always heard that 1/1.5x focal length when handheld is a >standard no matter what the camera/lens. Should I expect >better especially due to the VR?
No. The situation is counterintuitive because the ultra-high resolution of the latest sensors is capable of recording the slightest movement. So at high shutter speeds - say, above 1/500th - the operational frequency of VR element shifting can sometimes be a source of softening.
VR is not really designed to be left on at all times. Photographers who do so run the risk of developing sloppy handheld technique because of the impression that VR can contribute to sharper, steadier shots of normal exposures and using a 1/1.5X setting.
I think VR is designed to enhance a photographer's ability to get something usable at slow shutter speeds which, absent VR or a tripod, would normally result in blur, and to get steady shots in low light while keeping ISO out of the stratosphere. Despite what I said just above, too, about the possibility of inadvertently creating a situation in which sloppy technique creeps in, VR can certainly be useful in situations where footing is slightly unstable or where a shot has to be made too quickly, and so on, even when good light provides an uncompensated shutter speed that is fast enough to freeze subject motion or overcome slight physical tremor.
A photographer who inadvertently presses down the whole camera slightly when fulling pressing the shutter button will almost always end up with soft or blurry shots no matter what sort of shutter speed or VR is being used.
There's more, but you get the idea.
I think the 1/1.5X 'rule' is like the Pirate's Code . . . "more of a guideline really."