Apart from the singular proviso:

The camera's viewfinder defaults to automatic brightness mode, with 'exposure simulation' mode enabled with a half-press of the shutter release or by pressing the exposure simulation mode button on the front of the camera. The viewfinder reverts to the default automatic brightness mode after each exposure.

Douglas Herr really enjoyed the Leica. His review is a good read with great photos. And it's one that makes it much harder for me to wait for mine to arrive.