They are all fairly new, and there has not been enough time to publish comparison shooting with them.
All three save in RAW format, and have image stabilization.
THey are all P&S size. The Leica is the lightest, and the Canon is twice the weight of the Leica. Either the G9 is built with a more robust body, or Canon just installs extra ballast weights.
The Canon and Richo can use an external flash. The Canon can make use of most of the functions on their top-of-the-line flash unit.
The Canon has a Leica-look to it. This is cool, because Leica cameras are cool.
The Richo can produce a wider angle image than the other two cameras.
The Leica and Canon have 4X optical to Richo's 3X optical lens.
I can't find much good data on the Richo or Leica; but I do know you can get a
lens adapter for the Canon G9, that attaches to the body. When this is in place, it will protect the delicate lens mechanism, while in use. You can also use a polarizer on that adapter, as it sports a 58mm filter thread at the end.
Leica $600
Richo $550
Canon $440
Is there something about the Richo or Leica that makes them worth an extra $100-$150?? Are they water tight, or dust proof? These would be good things.
Nikon also has a camera that fits into this group also. The Nikon P5100 or P50. But; they dont save in RAW format.
Does this help to make a informed decision?