User Experience
Sigma and Canon make a case that basic guiding principles don't matter as much as execution when it comes to interface design. In organizing controls and choosing what has a physical control and what has a menu item, Sigma chooses simplicity pretty vigorously while Canon embraces Swiss Army Knife-style inclusiveness with equal gusto.

It's a battle that neither side wins. Sigma makes some wrong choices, allowing direct access to too few controls, and putting real basics such as white balance and ISO in menus rather than on buttons. Canon provides a dial for ISO, but jams plenty of its goofy kid stuff -such as “My Colors” - next to important controls and lards the G9 with useless settings including a choice of shutter sounds and startup screens.

Canon compact cameras, from entry-level to top-end, have a useful menu hierarchy, the most fundamental part of which is a set of options available from a “function” button, rather than from the menu button. The function options crowd onto the live preview, offering White Balance, My Colors, Bracket, Flash Compensation, Meter Pattern, Neutral Density filter, File Quality and File Size. The interface would be more streamlined and clearer if Canon dumped My Colors and slipped File Quality into File Size.

The Sigma DP1 menus require more of an overhaul. At the very least, ISO, meter pattern, autofocus and bracketing Other items that should be changed rarely or never, including contrast, sharpness and saturation, color space, and color mode, should be in a separate menu, out of the way.

Though the Canon G9 is arranged more cleverly, it's not all that much easier to use than the Sigma DP1 because Canon squeezed in so many marginal options and functions.