Hi CSG
I have been through quite a few 35s, as it my favourite focal range for rangefinder. I recently sold a broken version IV 'king of bokeh' Leica Summicron f2 and a Nokton 35 f1.2 to fund new lenses.
I have bought the CV 35 f1.4 and the Zeiss Biogon f2. I haven't had the Zeiss long enough to develop the films yet, but I have developed a few from the CV 35 f1.4.
I like the CV 35/1.4 a lot. It is a nice small size (smaller than the Zeiss), it is made well enough, and it is of course very fast - as fast I usually ever need. I've had no bad bokeh issues - it has worked so far really fine at f1.4.
I bought the Zeiss 25/2 for 2 reasons. The first, somewhat silly, because I have just bought a new Zeiss Ikon (one of the few 'new' RFs I have ever bought) and I wanted a shiny new Zeiss lens to go on it. The second reason was I loved the colours from the photos I have seen with this lens, perhaps more than any 35 I have seen. I wanted to use it for colour film but thought it was bound to be good enough for black and white too.
I have the CV 35/2.5 too. It's a great high contrast colour lens for travel and outdoor bright photography. Sooo small too. But not quite fast enough for an all round lens.
I sold the Summicron as it was falling apart and the Nokton f1.2, although it is lovely as leicamatt's photos show, because it is stupidly big and heavy for an RF and I appreciate small and light lenses for my 35mm gear.
If I could buy only one of the above, it would be the CV 35/1.4 because of it's speed, size, versatility and size. Get the single coated version, much nicer with black and white.
But the truth is any of the above lenses are quite capable of producing great 35 photos.
And now a silly photo, using the CV 35/1.4 wide open using the low light reflection from a black door in a public toilet