You'd rather have stuff shifting around in the camera body?I'm more interested in the "to IS or not to IS" debate. I'm really uneasy about stuff shifting around in the lens - it's a delicate enough pice of hardware. The Pentax system seems a better approach to me (not to mention cheaper and backwards compatible).
If you have an extensive collection of high quality, fully compatible, lenses that you're actually going to use then you should take that into consideration.