It is not so much the camera but the lens.
The Nikonos Lens is specifically designed for undewater use, so is very very good.
The body just has the metering and stuff.
There is another swiss made camera called subeye. Reminds me of hassleblad. This camera can use both Nikonos Lens and dome port lens.
Once the lens has that extra layer outside, somehow the colors, dimension, vividness... seems to drop. This is just my opinion.
But in terms of digital stuff, so much easier to get to a decent level of competence using a digital camera.