But have not used it underwater.
The Ike housing is bigger, but then again its much more "beefy" in construction. It would have to be bigger
The handle alone makes it significantly larger (I have the single handle; the double, which is an option, is even bigger, of course)
I don't find it problematic though - and it is extremely-well balanced, requiring very little effort to maneuver once underwater.
I got mine wet the other day, and will do some more playnig with it Sunday, assuming the seas lay down for me. My initial impressions of both the housing and camera in actual use were very favorable.
The "holddown" design is interesting. Basically, the buttons that have this function have a "cut cam plate" under the button. You can lift and rotate the button to "press" it by allowing the knob to drop into a detent, and when you release it, it stays down - and the button stays depressed. To release, you pull and rotate back to the "up" detent. There are four "locking" buttons - the two on the top do double-duty (they can press either of two on the top of the camera); you never need to press both of those at once, so this works very well. The other two on the side of the camera may need to be pressed at the same time; they have their own individual "locking" controls.
The only gripe is that the buttons for the rosette on the back of the camera are close together and its possible to press more than one, which is undesirable. However, I see no way Ike could have gotten around this - the buttons are close together on the CAMERA! Not a big problem in warm water, but with heavy drysuit gloves you might be less happy with that set of buttons.
One nice thing about the 5050 is that you can turn the display off when you're not using the camera without shutting it down - it comes back from being "asleep" in this fashion much faster than a cold power-up (since the only part that's off is the LCD), and with the LCD turned off power consumption is very close to zero.
