Two very different watches, both very special. If forced to compare I would say the CS will be the more reliable considering it's the newer model, manual wind and has no complications. The CS is IMHO the perfectly executed watch by Journe. The dial and movement like his other pieces completely original and innovative. The gold movement is stunning and can capture one's attention for indefinitely. It's incredibly comfortable to wear and absolutely suitable for 7 days a week. The Octa Chronograph, with 60 minute counter is wonderful in it's own right. It's automatic has tons of character with it's two push buttons that have the same knurling as the crown. The dial has a nice technical feel while also keeping a bit of delicateness. As for reliability, you can wear every day without a problem. Some earlier models (brass movement) had some problems which are well known and corrected. Comparing to the CS is difficult because they are very different. I enjoy having the date and a chrono always can keep me busy. The chronograph will also be discontinued in time. The Centigraph has stolen the spotlight. Versus the Datograph... now a much harder comparison. It's case is thinner, more elegant, and again has the the 60min counter vs 30min. The Chronograph is definitely more comfortable to wear because the Datograph is heavy. However, the movement of the Datograph IMHO is hands down the winner.
I know you have a difficult choice ahead. I don't think you can make a bad decision.
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