The only control that is not accessible is the power zoom rocker on the kit lens - everything else works. Zooming works via the zoom/focus ring, but if you want to use zoom and manual focus, you have to switch via the menus. There's also no way to close the pop-up flash without opening the housing, and no way to disable it via the camera controls once it's open, but it's possible to trick the camera into thinking the flash is closed - there's a small magnet in the pop-up flash, and probably a hall effect sensor underneath it, so if you take two small but strong magnets and place them on the housing's back door, one inside and one outside, you can use the outside magnet to slide the inner one to the flash position and this will trigger the hall effect sensor.
One minor annoyance is that the two top knobs contact the camera dials edge-to-edge, so you have to rotate them in the direction opposite to the one you want the camera dials to move. Obviously this renders the markings on the mode dial knob thoroughly useless, but the housing is translucent, so you can peek inside and see the actual position of the mode dial, even when the sun washes out the screen completely. The rear dial has an extra sprocket between the knob and the ring that contacts the dial, so it spins in the proper direction.
A6000 and A6300 have a single C1 button on top, near the shutter button, while A6500 has C1 and C2 buttons in a slightly different location, so the housing has three buttons on top to cover all possibilities. There's also a few extra plastic parts included in the kit for fitting an A6000, but I don't have one to test how well they work.
The 16-50mm lens, when extended, comes up right against the port glass - I don't think there is even enough space to fit a filter. If I don't remove the lens cap prior to inserting the camera into the housing, it bumps into the glass and causes the lens to retract.
There's a leak sensor at the bottom of the housing - I don't know how well it responds to actual leaks, and I hope to never find out, but touching it with a finger causes it to flash a small red LED and beep fairly loudly.