I've got a Canon A610 with the Canon underwater case and altho I've never tried the video feature underwater, it works fine above. The underwater pics are very good, but I do miss the big old strobe on my old film unit. One issue I have with the underwater digitals is a problem with using the lcd screen. If you have enough light to take good pics, you can't see the screen well enough to use it,and have to rely on the eyepiece. In that case, I miss the big gunsight on my old unit.
All in all, the digital is much better.

Been there, done that, the washing machine ate the T-shirt