Well, the Zeiss lenses will have the advantage of being in production, rather than being available once in a blue moon on eBay. Yes the smc-a 85/1.4 is absolutely peerless; it as also pretty darn scarce on the open market, and therefore very, very expensive even when very, very used.
I would rather have a smc-a 85/1.4 but as a second best, the Zeiss is a very decent alternative, judging from reviews of the ZF mounted specimens.
Men, said the Devil, are good to their brothers: they don’t want to mend their own ways, but each others.
-- Piet Hein
Well, the Pentax 24 and 20 are no great shakes, good solid lenses but nothing special, a couple of Distagons in that range would likely be welcomed. The 15/3.5 is a Zeiss design (Also shared with the Leica Elmar-R 15/3.5). From 28mm and longer the Pentax lenses are world-class. In some cases (Notably the A* 85/1.4) the Pentax lenses blow the Zeiss versions out of the water.
We're talking here about a new row of ZEISS lenses, with an PK-mount for all analogue and digital PENTAX and SAMSUNG SLR's etc.. They are not coming out of the old drawers, they are brand new improved lens designs. But, it may takes a little while, to be able to buy them. Good stuff takes a while!
All new lenses are "special crap" for photography, Zeiss included, and most cases will not fit into requirement (or standard) of serious photographer. Many like that new lenses just because of "low" personal photo-standard, or they never saw work of a good lens.
The point is that new lenses are produced out of glass without Pb, Zeiss included.
Manufacturers have nothing to claim on their lenses except "resolution" and I never had a look at photograph under microscope counting lines per milimeters. Photography is about life, people, conditions,... blur but not sharpness, not about lines/mm. Now they are introducing "NEW" lenses with Aspherical elements, means they cannot get correction, and never saw good bokeh with that lenses (even and Leica included in some degree).
I have Nikkor 2.8/55 micro and will probaly get one more. I have no intention to even look at "new" Zeiss F2/50 MACRO. It cost well over $1600 (when include all payments) while Nikkor I can get new for $350. Even, I am positively sure, comparing photographs from that two macro lenses Zeiss will get very hard time to come even and close to Nikkor. Zeiss is still not out with that lens but to me as photographer what they can say opposite? For sure nothing more than e.g. 300 lines/mm. It means nothing to photographrs.
"... We're talking here about a new row of ZEISS lenses, with an PK-mount for all analogue and digital PENTAX and SAMSUNG SLR's etc.. They are not coming out of the old drawers, they are brand new improved lens designs ... "
Looks like you are from Zeiss, and it is fine. But is that company so low today that uses consumer market jokes to sell? Good luck. Photographers need Zeiss, but not Zeiss in that shape.
The Zeiss/Cosina lenses in "M" mount are getting fantastic reviews. Why shouldn't the designs for SLR's be equally good? The Zeiss designed lenses made by Kyocera were very good also. Zeiss installed a very elaborate quality control lab at Cosina to check every single lens that comes off the production line, and I am sure that they are not passing sub-standard units.