I am the proud owner of a new Chronometre Souverain. I looked very closely at an Octa Chronograph as well and it was superb except for a misaligned chrono hand, which the factory corrected straightaway.
It was a super tough choice, but I opted for the Chronometre Souverain as it is hand-wound and exceptionally clean and simple and beautifully proportioned to top it all of.
But now, I'm dreaming about the Octa Chronograph. It will become rare in the Force, I assure you.