Compared to the Canon case I find the Sony case clearly-quality and thoughtful. It is also slightly negative balanced by variable internal weight discs. The Canon housing has significantly buoyant and without extra weights (to be of poor quality) I verissen many cropping up (surely a matter of practice). The keys are very smooth to operate and in particular the trigger is better to classes at Sony. The focus point can be very good "feel" and the super-fast and unerring focus of the WX100 has at ISO200 is a very high hit rate of sharp images. The colors in the underwater mode, I personally find a bit better than the Canon (there a little paler and slightly greenish, but you can certainly edit). Competitively, the Canon is of course at the option of manual settings, in particular the rapid Iso-change on the dial is great. Image quality / noise ratio is also very good and obviously in diving circles a fixed size. If you do everything right and the fish hold still, you get great photos. Disturbing I felt really just the stiff, not for me erspürenden trigger point in combination with the still significantly slower focus of G11.
The Nikon AW100 is clearly inferior to the two cameras in terms of image quality naturally. The only advantage is the portability. In addition, it tends to fog (Remedy: Storage in zip bags with Silikagranulat).
Conclusion: Canon and Sony make both super UW-photos, the Sony's but for me the more straightforward and user-friendly camera case combo with a higher hit rate on sharp and correctly exposed images.