If you are expecting the image quality of a DSLR, then you will be disappointed.

Overall their image quality is good but has limitations due to a small sensor.

The Sony is hampered by it 16MP sensor, which is noisy and requires noise reduction firmware in the camera.
This results in lowered detail - detail was the very thing the 16MP was supposed to give us.
The Sony also uses a 25MM wide angle lens which should have been used as a 28MM lens.
The right and left sides of the pictures are soft.
Here are some sample photos - to see the faults look at the pictures at full size (pixel peeping):

http://www.imaging-resource.com/PRODS/TX10/TX10A.HTM

The Panasonic offers a more sensible 12MP sensor and more sensible 28MP wide angle lens.
More detail and an overall sharp picture.
Here are some sample under-water pictures.:

http://forums.dpreview.com/forums/read.asp?forum=1007&message=39376954

If you are going to print 4 x 6 inch pictures, either camera's pictures will be fine.
But larger pictures will show their shortcomings.

Reviews by customers, reveal that some people experienced water in the camera when taking pictures under-water (both cameras).
I am not a fan of extended warranty.
But for a $275 camera you may want to think about it.
Make sure that it covers water damage.

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