I am Zeiss fanboy, and I was shooting with 50 1.2, which I had eventually sold. My Zeiss lenses are 85 1.4 and 50 2.0 macro. What could I say, 50 1.2 is worth shooting 1.2, when stopped down the picture becomes less appealing. But the 1.2 is generally not usable in terms of microstock photography, which I'm trying to focus on completely. Why I have bought 50 2.0 macro over 50 1.4: 1 I thought that I saw sharp lenses before buying this one... but when I did, I realized how wrong I was. It is really THAT SHARP, 2 It have unique rendering of out-of-focus areas, that no other lens can produce, and I really like it.
I asked myself a question - how often I will shoot 1.4 wide open for stock purposes and the answer was "not really often". So I decided to put my money into 2.0 and I really happy with this decision.
And the Zeiss 85 1.4 ... It's just beautiful, for me using it is very similar to sexual pleasure lol, I cannot be more specific, just love it full stop
Now the pitfalls. Manual focusing is the challenge... I remember how frustrated I was over 99% of my first images was out of focus... Live view improves focusing experience dramatically, but still.. Zeisses are not for quick shooting.
So if your main subjects are weddings, journalist-style shooting, buy Canon lenses, If you shoot advertising or microstock, or still life, I would recommend Zeiss.
Any other question - will be happy to help