[dpt2014]

The problem is that the 645 must be tilted on its side to get portrait orientation, the RB has a rotating back that allows the camera to stay upright. That makes the RB much easier to use than the 645 in portrait orientation.

I understand, but I rarely shoot in portrait orientation. So I don't value rotating backs very much. That's been a point I've made and I thought I was being clear, guess not.