One small area of concern is the battery life indicator. The camera is powered by a small 740mAh Li-ion battery, the same cell as the FE-250 and many of Olympus' other compacts, but here it has to power a longer zoom lens and the anti-shake mechanism too. Olympus makes no particular claim for the battery duration, but I found that the on-screen battery duration indicator turned red after only about 140 shots. However I carried on shooting to see when it ran out, and the camera was still going strong after 300 shots, about half of them with flash. It seems the battery indicator only has two positions, "Battery Full" or "Red Alert", making it a bit hard to tell when you're likely to run out of juice.
The image stabilisation system, which is I believe of the moving-sensor type, is reasonably effective, but is not the best I've ever seen by any means. I was still spotting camera shake on about fifty percent of shots at 1/30th of a second. In other aspects of image quality however the camera performed very well. It uses a 1/2.3-in sensor, which is slightly larger than most 7MP compacts, although not as large as the 1/1.8-in sensor in the FE-250, and while it did produce slight image noise even at the lowest setting of ISO 80, it didn't really become a problem until ISO 400. Dynamic range was about average for a small-sensor camera, with some highlight clipping and limited shadow detail, and I did find that the exposure system was inclined to under-expose slightly, which is usual for an Olympus camera. Colour reproduction was very good though, and the overall level of detail was good for a 7MP model. The lens was particularly good, with no distortion at either end of the zoom range, and only a slight softening at the far corners of the frame.
The Olympus mju 780 is a good all-rounder, with superior build quality, stylish and practical design and good performance including low light focusing. It has an effective mechanical image stabilisation system and its wider-than-average 5x zoom range gives it versatility, however apart from these it is distinctly lacking in features, and the image quality could be better too. All in all though it is a good camera for outdoor snapshot photography, and especially for social or holiday photos.