Canon seems to be experimenting with the design of its snapshot cameras, and this is the most radical change yet. The new incised buttons certainly give the SD790 IS a novel look, but they take a little getting used to; they don't have a lot of travel and need to provide a little more tactile feedback. The control dial has a better feel than that of the SD890 IS, though it still flies a bit too freely and doesn't provide hard stops at each of the options. Nevertheless, the new controls fall just over the "I like them" side of the fence.
Part of the new design is a shallow, angular crevasse running the length of the top of the camera, where the microphone lives (that tiny dot near the power switch). While shooting movie clips, wind noise was quite severe, sometimes obscuring my commentary entirely. I suspect that was partly caused by the wind whipping down that aerodynamically friendly channel and right over the pinhole mic.
One of Canon's helpful features is Focus Check, which either provides a review screen like this after every shot or allows you to display it during playback. In practice, I ended up disabling the every-shot review for getting in the way of shooting.
The SD790 IS has one of the best noise profiles we've seen in a point-and-shoot camera, especially given its relatively low price. A bit of blotchiness begins to appear at ISO 400, but it doesn't get serious until ISO 800, and blurring doesn't eradicate detail until about ISO 1600. I consider the SD790 IS' photos quite usable up to and including ISO 800.
The SD890 IS does exhibit some symmetrical barrel distortion at its widest angle of 35mm-equivalent, but no more than the rest of its class. Plus, it's easier to correct for symmetrical distortion in software than asymmetrical.
We were surprised by how sharp the SD790 IS' photos look. By the numbers, it's sharper than any other Canon compact camera we've tested recently, and bested only by the Pentax Optio S10 and Fujifilm FinePix F50fd in its class.