I dive with 3mm gloves and have no problems with the buttons on my Ike housing for my S80. Great camera, incredibly well-built housing. The main concern with the S80 at this point is availability of replacements, should a flood occur.
And no matter how careful you are, they can and will occur when you least expect it. My only floods with my Ikelite case have been entirely user error, I will say.
Despite what post #3 says "is very susceptible to moisture getting into it an causing it to fail" that is completely untrue. The S80 is no more prone to "moisture" problems than any other camera. Any camera can flood. And that's more a function of the housing than the camera, so blaming a model of camera for floods is disingenuous at best.
The S80 takes some of the best, sharpest, and closest to dSLR photos of any out there. It costs more, however. It is definitely smaller and easier to pocket compared to the A series cameras, although nowhere near the SD series (which lack manual controls). The battery pack (and charger) also travels a lot better than handfuls of AAs and a bulky AA charger. A spare battery pack in your pocket also takes up a lot less room than 4 AAs jumbling around.
Then again, the A series cameras are a lot less money, for a very fine camera. Just not as good as the S80, IMO.
The S80 works just fine with the Ike housing and diffuser. No flash problems. The Canon housing is less bulky, however, especially if you add a handle and tray to the Ike housing, which it really needs because the OEM "strap" is a joke, while the Canon gets along fine without it. Both are pretty much equally bulky once you start adding strobes and trays, of course.