The primary reason for a digital SLR is the size of the sensor. The APS-C sensor is about the size of a postage stamp. The Canon G1X is just a tiny bit smaller than that. Typical point and shoot digital cameras have sensors roughly the size of your little finger-nail. That means, the more "pixels", which really are called "photo-sites" on the sensor, the more electronic interference (noise) is created in taking the picture. That noise is what looks like grain when you see your images on the computer at 100 percent size. They look great when small, but, zoom to the actually size and they can look pretty bad. That translates to very poor image quality on anything over a 5x7 image or anything for print publications.

Of course, most people think the biggest benefit of digital SLR cameras is interchangeable lenses, and while they add a ton of shooting options, they are expensive, precision instruments, and can be damaged by dust, moisture, etc. I had pollen on the sensor of my professional DSLR and it was difficult to remove. It's either take a DSLR for road trips and never change a lens, or opt for a really high-end point and shoot. I ordered the Canon G1X for that reason.

For the record... the clearest DSLR ever made was the Nikon D2H. It is just four-mega-pixels. I am of the school of thought that the higher above ten-mega-pixels you go on an APS-C sensor, the more you degrade the image. It is far worse on the tiny sensors in P&S digital cameras.