The big problem for me with night time photography is the light output from the EVF. I've only tried two so far, my own G1 and a Nex 6 and both were unusable and caused immediate and sever eye strain due to the high light output which was too high for me even after adjustment for best effect. The back screen is the only option to avoid the little torch shining directly into your eye but the dynamic range of the display could be an issue, again my G1 is unusable but I didn't try the Nex 6. So, my advice is to try before you buy otherwise you could end up with a camera which is great in daylight, acceptable in low light and completely unusable for night time shooting.
