Zeiss is better.
In terms of the field of photography, excellent lens selection Leica is greater than Zeiss, because Zeiss left the field of photography for a long time, today's Zeiss lens on the market, are Zeiss authorized by a third party production, such as Sony camera Zeiss lens, is authorized by Zeiss to Sony's own production to play on the Zeiss logo, such as the Leica M mouth of Zeiss lenses is simply to ensure that the good energy to pay for buy zeiss logo of their own production.
If you jump out of the field of photography, Zeiss is a supplier of NASA, there is zero expansion glass technology, the Hubble telescope in space, the lens of the satellite around the Earth in various countries, a lot of national astronomical observatories large astronomical telescopes look, the field of medicine has a variety of optical equipment.
There are also a lot of military equipment on the optical technology, there are Zeiss, and Leica only photographic lenses and microscopes, total station. Also Leica was acquired and sold for the first time by other companies, while Zeiss is supposedly forbidden to sell by strategic companies, so Zeiss is better.