Not really familiar with either camera but one thing i would suggest:
Underwater is much different than shooting on land. WIth the much lower light levels, you need to do some adjusting.
Therefore, you need to purchase a camera that will give you full manual control over shutter speed, aperture, and ISO settings.
Program modes that work well on land do not work well with underwater. These modes like to pick strange settings that will give very blueish, washed out photos.
Having a camera with full manual control will enable you to avoid this.
Also, before you buy, do a little research with some of the online photo shops to find out what cameras have underwater housings available. Its no good to buy a camera and then find out there is no housing available.
Good luck with whatever you purchase