I'm just sending the first three 'Classic' lenses back today, having used them reasonably extensively on a 503cx. Optically they appear identical to to the existing 50/4 Distagon, 120/4 Makro-Planar and 180/4 Sonnar except that the manually adjusted floating element on the Distagon is fixed (no control ring). They look very retro in silver (like pre-'72 Hasselblad lenses) and needless to say performance is excellent. I shot mostly Velvia 100 and Ilford HP5. For black and white, these lenses are magic. Never mind the 'Leica Glow': here you have the 'MF Zeiss Glow'.
Specs are available on www.zeiss.com.