The mju 790 SW is waterproof to a depth of 3m, shockproof against drops of 1.5m, and is claimed to withstand temperatures of minus 10 degrees centigrade. While the first two figures are not in doubt, that temperature claim requires closer examination. As I've pointed out here, most digital cameras are perfectly safe in sub-zero temperatures, as long as you take some simple precautions against condensation. There are many reports of ordinary digital cameras being used at temperatures as low as minus 40 centigrade without any serious problems. Of course being waterproof the 790 is largely immune to condensation damage, and a reading of the manual reveals that the performance of the Olympus-branded xD-picture cards and the Lithium-ion battery has been tested down to minus 10 and found to be okay. Still, like most marketing claims, it's not really as much of a wonder as it sounds.
Apart from the other models in the mju SW range, as usual there is really only one rival camera with which to compare the mju 790 SW, and that is the Pentax Optio W30. Both are 3x zoom 7.1MP compacts, both are waterproof to 3m and both are compact enough to slip into a pocket. However the Pentax lacks the shockproof claim, and it has to be said that compared to the stylish mju 790, the W30 does look a bit plain. The mju cameras have always been premium products, so it's no surprise that the 790 SW is more expensive than the Pentax, but not by too big a margin. The Optio W30 currently sells for around £140, while the mju 790 SW is currently available for around £170. However compare this with other premium 3x zoom 7MP cameras such as the Canon IXUS 75 (£135), or the Nikon S200 (£100) and it starts to look a bit expensive. I guess it depends on how much you feel you need a shockproof camera.
Except for from its adventure-proof design, the 790 SW is a fairly basic point-and-shoot camera with a rather limited range of features. Main shooting mode selection is via a small dial control on the back plate, positioned so that it doubles as a thumb grip. Available modes are full auto, an anti-shake mode that simply boosts the ISO setting, a choice of 23 scene modes including three underwater settings, video mode and the useful Guide mode that has appeared on a number of Olympus compacts. This is a good feature for beginners, since it acts as a live tutorial in basic photography, including automatically setting the camera to cope with unusual situations, but more experienced photographers will seldom use it. The video mode is somewhat improved over the disappointing 770 SW, since it does offer VGA (640 x 480) resolution at 30 frames per second, but only in 10-second clips. 30fps VGA video is pretty much a standard feature on most recent digital cameras, so Olympus is lagging a bit here. It's also lagging in menu design; the 790's main menu is just as annoying and pointlessly over-complicated as ever.