In my experience the 24–70/4 isn't marvelous but for most purposes it's still fine. A couple weeks ago I did a 14x21" print comparison (as large as I can make with a 3:2 image) between some A7r2 pics taken in daylight with it the lens at 24mm and pics of the same scenes taken with a Zeiss 25/2 Batis. Tripod, same apertures, etc. I can't see any meaningful differences between the zoom pics and those from the 25mm. In low light situations I'd opt for the Batis, otherwise it comes down to whether I want more compact (Batis) or more convenient (zoom).
-Dave-