The comparison is a really good question because the differences between the lenses ultimately force us to think not about what others value, but we ourselves value.
First, some background: I don't have both. Back Alley does. I had the Zeiss 35/2 until I gave it to my GF when she gave me an R4A. I also had a CV 40/1.4, which I did not like. I'm preparing to buy the new C-Biogon 35. I've been tempted on paper by the CV 35/1.4, but have never been impressed by the image results, don't like tabs, and already have a super fast 35 that produces a remarkable final image.
I've read Matt's blog and looked at his photographs, both now and before, and I admire his balanced assessments and his compositional vision.
I would suggest reading his preference for the CV 35/1.4 in light of his earlier review of the Biogon alone (on the same site). The view of the CV 35/1.4 is complicated and occasionally contradicted, in my mind, by his earlier review of the Biogon. In the former (chronologically later) he says the Biogon has an inferior build ("Build quality: The CV is just better built than the Biogon... My Biogon has a bit of wobble in the lens barrel and doesn’t mount quite as snuggly as the CV"); yet in the latter one (chronologically earlier) he says it has impressive build ("Build quality & Handling: The lens feels very sturdy. It mounts securely"). The ZM lenses I have all have noticeably better build than any CV lens I've ever touched. Even with the sample variation, I don't think I'm just lucky. The "character" of the CV lens about which Matt speaks--and he is quite frank about this--is due to its greater propensity to flare and the much higher level of distortion ("the CV’s incredible barrel distortion").
The conclusion I draw is that Matt has grown accustomed to the handling of the CV principally because of the small size and the ergonomics of the tab ("this small size would become so integral to my appreciation of the lens"). It seems to me his argument is NOT about the superiority of one lens over another, but really about how subjective feel in using a lens might actually be one of if not the most important factor in final image composition.
No amount of professional experience, artistic vision and gear knowledge is going to steal these truths from my eyes: A higher percentage of photos taken with the CV are less appealing to me.