What IS and VR do is compensate for YOUR shake and only up to a point, they do NOT compensate for subject's movement, so you still need a tripod for some types of shots...
I guess you meant to say that IS/VR does not help also in some other situations (e.g. 5s exposures etc.) except when there is subject's movement, and that tripod is needed then, but the sentence could be understood wrongly, that you meant to say that tripod is going to help with subject's movement.
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The one very useful situation is when one lays camera/lens on some fence or some tree trying to get longer exposure (e.g. 2 or 3s), then IS/VR will be very useful to compensate for small movements which still exist, thus helping to obtain much sharper photo without tripod in situations that even IS/VR does not help with hend-held camera.
Also, image stabilization in lens usually have two modes: normal one, and the one for tracking moving object, so-called panning. The first one stabilize lens along both axis, while the second one does it only along one (usually vertical).
Direct comparison is not that easy to make, if you shoot with minimal recommended shutter speed, but VR enables you to go 3 or 4 stops below that, meaning you can shoot at 1/30s with 200mm focal lenght (e.g. with latest Canon 70-200 f4 which enables additional 4 stops).
you can see canon's example photos here:
http://web.canon.jp/imaging/lens/expression/index.html
Bear in mind that neither of these photos would be that sharp without IS. Also, in some lens IS degrades picture quality, but usually very slightly, so there's no worry except if you use it for normal shutter speeds that do not requier IS/VR (where you can obtain slightly better sharpness with IS/VR set to off).