Both adaptors work very similarly to all the other lens mount adaptors available: you lose AF, AE and VR, but they are chipped to enable focus-confirmation: you see the red squares light up when focus is acquired, just like a Canon lens.
As with adapted Leica, Contax, Olympus or Nikon lenses, one typically composes with the lens wide open, then stops down to allow the camera to meter through the lens.
The lever-operated version is simply more expensive to produce. Some prefer to rotate the lens in the mount; others prefer to select the aperture with a lever. I will be offering a crossgrade option in due course to allow buyers to try both.
More details coming soon . . . .