Compact cameras might be useful up to ISO 400. Might stretch to iso 800 for small prints.
The top ones are the pany lx5, the oly xz1, and the canon s100. If you want a camera to use on land, that pretty much demands a view finder of some sort. The nikon p7100 is really looking awesome, for it's combination of zoom and WA. It has much faster and very reliable autofocus than the canon g12, or the older p7000.
All of those have M mode. The nikon is the best for ergonomics - with 2 separate big knobs. The lx5 has one knob on the upper back, which switches back and forth when you click it. The xz1 has only a menu based system, when in a housing. Just click 1 button, and then the 2 sideways buttons are aperture, and the 2 up and down buttons are shutter speed.
The cheaper mirrorless cams, with cheap housings are the oly epl2 and epl3. They are adequate IQ up to ISO 1600, and usable at 3200. They have great photographer, friendly features, like a tunable lowest shutter speed in A mode, with flash on, and the ability to use auto ISO and metering in M mode, to set the ISO..
But the ergonomics is really not good! They have no dial for adjusting settings. So the interface, in a housing, is the same as the xz1! Click once to get attention, then click one of 4 buttons to increase or decrease the f-top and shutter speed. Every shot, you still have to do that first extra click.
The other thing I didn't like about the oly PENs, is the burst mode is unusable. It just goes into replay mode, showing you what you just shot! So it is point and guess. And the EVF, would not work any better, since it just shows the same thing as LCD.
The Panasonic gf2 at least has one extra wheel on the upper right of the back, for adjusting settings. But the A mode SS goes down to 1/60. Too slow. And the M mode has no auto ISO possibility. The second fastest burst mode is reported to allow live view between shots.