I love Langes and am a fan of the brand.
On the contrary, to be completely honest, I am not a fan of Zenith but that's mostly because I am not familiar with the brand.
However, for Langes, the Zeitwerk is the least appealing to me from a looks standpoint. I appreciate its innovative functions but not its looks. I know of many Lange friends who love it but not me.
the Zenith you are considering is a beautiful piece of traditional haute horology on the other hand. I saw it once in the Singapore boutique and it's lovely to admire.
I will pick the Zenith between the 2 
and this is coming from a Lange lover!
Cheers
Robin