Hi surf...

The PDX has the best 16:9 mode of the three, the other two have the better dynamic range and light sensitivity, as well as better manual control. Do you think you might use the camera for anything other than diving? That might better inform you on your decision. Overall, I say that, unless you're hot for 16:9, either the VX or the 170 will serve you best, and if money truly isn't a problem, go with the 170 (for slightly more refined manual controls and better/more audio options).

Out of curiosity, have you considered also Panasonic's offerings within this price range?

Shawn

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