so I have both as well. The "classic" yellow gold/silver Lange 1 and the red gold/silver CS.
They're oil and water but, last time I checked, most of us need both oil and water.
Interestingly, I was quite sure I'd get the platinum CS, but when I saw the red gold one, I was done for.
Date functions are useful, but in this day and age of the ubiquitous cell phone and blackberry, do we really need to make that a go/no-go for our time pieces?
My slant in watch choices is face design and the overall look and feel. Movements are important but not the first thing. To me, each of these watches expresses something essential about timepiece design. The Lange 1 is cooly modern, intellectual, Bauhaus, Mies van de Rohe. The CS is, on the other hand, extravagantly post-modern, playful, neoclassic, Frank Gehry (OK, not quite Frank Gehry, that would be Vianney, but maybe Michael Graves?). Both offer the highest degree of mechanical craftsmanship and exquisite, jewel-like construction.
So start saving. You know you can't eat just one.