Glashütte Original

Hi all I have an opportunity to buy a Glashutte Original Senator perpetual Calender at a good price, the older one, the one with the guilloche dail. I was wondering if I should buy it or hold off for the newer one? What are the differences between the two... 

If it is a Cal 39 I think there are arguments to prefer the newer Cal 100 (which is more interesting, has two barrel springs, and fits the case better, IMO) - although the Cal. 39 is of course a well-tested workhorse. I agree that the guilloche dials are ... 

. . . are all fitted with the cal 100 movement. They were available during the roll-out of the cal 100 movement in 2005 . . . [photo credit: Marcus H] . . . and discontinued around 2008, to the best of my recollection. I'm not aware of any appreciable cha...  

Thank you Art for the info, you have helped me make up my mind. Just curious, which one do you like more?

. . . matches up more coherently with the flat dials, but in rose gold, the engraved dial adds a measure of visual intensity that deflects some of the opulence of the case, which is beneficial, in my view. My favorite cal 100 perpetual, though, and by a l...