The degree to which distortion is visible and bothersome depends on the type of photography, so it may be in the work you're doing you simply don't notice it, or it is not detrimental. For the stuff I do, it can be a real pain, and these Zeiss lenses, for the most part, are no better corrected for geometric distortion than their Nikon/Canon counterparts. It annoys me, but I think this might also be part of the digital crossover intent. Simple geometric distortion can be corrected with software so my sense is in general the latest wide angle and normal focal length lens designs from Nikon, Zeiss etc attempt to optimize for other things like speed and bokeh rather than distortion. For example even Nikon's new, VERY expensive 24mm prime shows visible barrel distortion.

Anyhow I guess everyone had their preference and taste. Interesting discussion.