A. Lange & Söhne Datograph UpdownvsOmega Speedmaster Calibre 321 Chronograph 39 7mm

Owners widely praise the A. Lange & Söhne Datograph Updown for its exceptional movement finishing, with some calling it the "king of chronographs" and a mechanical wonder. Reviewers highlight its refined design, balanced dial with an oversized date, and the "buttery smooth" action of its flyback chronograph. The watch's 41mm case is noted as comfortable on the wrist, and its manual-winding L951.6 movement is described as a sculptural beauty with German silver bridges and hand-engraved details. On balance, owners and reviewers rate the A. Lange & Söhne Datograph Updown highly for its complex, hand-finished movement and sophisticated chronograph functionality.

Owners and reviewers widely praise the Omega Speedmaster Calibre 321 Chronograph 39.7mm for its historical fidelity to the 105.003, its superior finishing, and the tactile feel of its pushers and bracelet, with some considering it the ultimate Speedmaster. The movement's copper-plated finish and column-wheel chronograph mechanism are highlighted as distinguishing features. However, its high price, limited availability, and lack of hacking, anti-magnetism, and crown guards are noted drawbacks. Accuracy varies, with one owner reporting +20 seconds per day out of the box, while others cite better performance. On balance, owners and reviewers rate the Omega Speedmaster Calibre 321 Chronograph 39.7mm highly for its blend of vintage aesthetic, superb movement finishing, and comfortable wearability, justifying its premium price for enthusiasts.