I'm in a bad mood tonight (I had a bad day) so I might as well start a fight. The real question is why have a strobe at all?
Strobes are the product of the film camera age. They have a use in the digital age for 1) when it is too dark to take a photo; 2) when you need the strobe to "stop" action. There might be some other minimal reason for a strobe but I can't think of it now.
Digital cameras that have the ability to manually "white balance" can adjust (correctly I might add) the colors according to available light. So, at 60 feet, without a strobe you can "show" the camera what white is and it can adjust all the other colors accordingly, giving you perfect pictures at 60 feet without a strobe. Film can't do that without a strobe. The reason is that film is set to certain light conditions (ie daylight) at the surface. Since those conditions don't exist at depth, you need a strobe to make the proper light exist. With digital, forget the strobe unless you are in poor visibility, night diving, or want to stop extremely fast action.
The C5050 will allow you to adjust the white balance; I don't know about the Sony.
The C5050 gives you a macro and super macro setting; I don't know about the Sony. Macro is used for the best photos of most of the photographers of this website. I don't think super macro is used that often. If the Sony has macro, it will probably equal the 5050 macro.
From what I've learned, the C5050 allows you to buy a cheap housing; I don't know about the Sony. Ikelight makes a housing for the C5050 and "Ike" from Ikelight reads this website. His housings have been around for a very long time and they obviously have a good reputation...but they are more expensive. I would have bought an Ikelight housing but I ran out of money so I got the PT 015 and love it. I would have been proud to say I owned an Ikelite (or Ikelight) housing, and it has some great features that the PT 015 doesn't have.
The C5050 gives you control over most of the camera settings or you can use the program mode and it's a point and shoot. I don't know about the Sony. If you are not interested in learning how to set the camera for the effect you want, then the manual settings of the C5050 have no value to you.
The C5050 is a 5 megapixel camera; I don't know about the Sony. This is only important if you are blowing your pictures way up or cropping most of the photo out. An example is if you want to crop all but a small part of the photo out--with a 5 megapixel camera, you have proportionately more pixels to work with in the cropped photo and can make a tighter, detailed crop, as compared to a 3 megapixel; which is proportionately better than a 2 or 1 megapixel.
My problem with the C5050 is that its auto focus is slow; I don't know about Sony. No one but me seems to have that problem. My wife has a Nikon D100 and trust me, the C5050 is slow. But, the D100 housing is about $1,500 and she'd kill me if I flooded her camera, so I bought the C5050.
Most likely, you will be happy with either camera. (Psychologically speaking, if you spend that much money on something there's no way you'll admit you made a bad decision.) So, look for the features you want and determine which camera has those features. A friend of mine just ordered the Olympus C740 because he wanted more control than the "D" version cameras (point and shoot) and he wanted the 10X optical zoom as opposed to the C5050 3X optical. I can't help but admit I wish I had a 10X for surface photos.
Having said all that, forget the strobe unless you want to take night photos and look for which features are most important to you and find those features in a camera and buy it. But, before you buy, call Ike (or search for other alternatives) to get the price of a housing 'cause without a good housing, you only have a land camera. Overall, I'm happy with my C5050 and my PT 015 housing.
Sailor