I'm not very well-versed in things PP, so I thought I would ask the cognoscenti their opinions about the various perpetual calendars (not the chronograph perpetual calendars) in the current collection. I guess that would include the several variations of the 5140, the 5159, the 5940 and the 5496 - have I got them all? I have some opinions of my own of course, and have tried them all on, but I am interested to learn how these are perceived among the better-informed. Feel free to comment on any aspect - aesthetics & design, readability, choice of metal, desireability/collectibility, etc. I have everything to learn...thanks in advance.