That's not just a moon phase, but a full calendar (or possibly annual calendar) and chronograph too. Certainly an interesting watch.
I had one of the first limited edition reverse-panda Transoceans soon after they came out, and while I kept it for a few years, for some reason I got bored with it quite quickly. Absolutely nothing wrong with the watch, but was just a little too...well, not sure really, but perhaps clinical - can’t really think of the right word.
Anyway, in the end I think I might have preferred a black dialled Grand Premier which seems a lot less clinical.