IS is useful in only one situation with a camera of only 3-4x zoom and that's only in low-light, where you must use a low shutter speed in order to get a clean picture without flash. The IS will stabilize the camera throughout the image capture process but still, the subject must also be standing still in order for the image to be perfectly sharp.
Fuji's answer to this scenario is instead of using a low shutter speed, use a high shuter speed by notching up the ISO. The high ISO's in Fuji cams are cleaner than other cameras at the moment. A high shutter speed will counter any camera shake and you also don't have to worry about the subject moving. Fuji solves two problems at one go by developing their ISO.
IMO high ISO is more important than IS.