I think what bothers me the most about the ZF is that apparently the RF patch does not move with the framelines, as they shift to compensate for parallax. So, at times the patch will be off center from the framelines. That could interfere with composing shots...
Other than that I think it is a nice camera. It certainly has a much better design for exposure compensation. The dial on the back door of the M7 is a joke.
I don't think the ZF would stand up to the same abuse a Leica would, but if you are a more casual shooter is sure is a bargain given the prices Leica is charging these days.