For me, ZenCash is more powerful. I'm not sure what the exact reason is for fully rebranding. Maybe only design & logo can be changed.
New logo represents our values, qualities, and technology, it is attractive and versatile. ZenCash expanded their brand to reflect its direction with technology advancements and social innovations! We are platform now and we have much more to offer not only "cash".
More details you can find in link below ->
https://bitcointalk.org/index.php?topic=2047435.msg44760929#msg44760929
