Lloyd Chambers is a bit unreliable with his praise. This lens appears to have weak extreme corners, like the 25/2.8 and 28/2 before it (I own the 28/2, great lens), and the 25/2.8 was also extremely sharp. Both have mustache distortion, the 25/2.8 about 2.3% max, and the 25/2 2% max. The old 25 already had great colour and contrast, and could focus closer, with somewhat messier corners. The main advancement of the new lens is improved CA, and a secondary aspect is the somewhat better corners. Considering that the old lens can often be found for 500 Euro used but in perfect shape, and the new one costs 1500 Euro or so, I think this lens is not really worth it. I picked up my ZF.2 28/2 for about half of this lens, and it is perfect with the packaging and everything, and is a great lens.
In summary, it is undoubtedly better than the old 25, but the price more than compensates for that, and we are into diminishing returns territory. I think Lloyd Chambers is fair on the old lens, but too easy on the new lens. I personally wish that Zeiss would make certain lenses 5% larger and fix those corners (25/2, 25/2.8, 28/2, 50/2MP).
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I had a Sinar 22MP eMotion 54 LV back for my Contax, and when it worked well, it was a fantastic combination, high DR, beautiful tonality, and fully able to extract the most from those awesome Contax 645 lenses. However, there was something not reliable about the combination and I had way too many exposure problems, so I sold it again. I think I would get a D3x before trying that again. I doubt I will ever need more.
Of course, if I had lots of money, I would love another MFDB, and were money more plentiful in my life, I would pick the P45+, and if it were much more plentiful, I would choose either Leaf Aptus-II 12, P65+ or IQ 180, the important thing being the full frame sensor.