Did you know that the perpetual calendar watch is actually based off the annual calendar watch and has only about 40 more pieces than the normal annual calendar?
I think the simple fact that the perpetual calendar can be achieved with only a few more parts than the annual calendar makes it rather unique. This also gives credit to the annual calendar that it is an exceptionally advanced annual calendar.
Because of this, I would be pleased to own either watch; but if given the choice, go for the Perpetual calendar because it is easier to set than the annual calendar. If you want to set the month in the annual calendar, you'll have to go through all the dates of the month until you come to the desired date in the desired month (that's a lot of crown turning). The perpetual has an easier setting system (but then you have the leap year to worry about).
Great watch! I'm surprised the Octa Perpetuelle is still available.