it is hard to say they if they are better than Canon lenses but to my knowledge Zeiss lenses are one of the top quality lenses you could find in the market (I wouldn't compare them with third party lenses like Sigma tamron etc )
Sony has been using zeiss lenses and I guess it is the lens why many people go for sony.
zeiss lenses also tend to be very expensive and the recommended prices for upcoming EF bayonet lenses show it clearly k:)
quoted from dpreview:Recommended retail price of both lenses:
Planar T* 1.4/50 ZE
$ 660
Planar T* 1.4/85 ZE
$ 1,170