Again, "OK" is really subjective. Again, no, I would not be happy with a sony cybershot from the various models that I have seen come through. Several models at least - I don't really consider sony's a real contender for UW work and don't keep up with every model - don't offer true manual control though they are marketed that way.
For me, I will not live without control of my aperture, shutter and ISO at a minimum. If a camera does not have those three things, I wouldn't be happy with the results because I've used cameras that limit that control and the results just don't work for me. And the difference in set up price just doesn't make sense to short-change myself. There are others who get results they are very happy with from models without those controls - so YMMV!