Omega Speedmaster Calibre 321 Chronograph 39 7mmvsSeiko Prospex SPEEDTIMER Seiko Brand 100th Anniversary SPEEDTIMER Limited Edition

The Omega Speedmaster Calibre 321 Chronograph 39.7mm is widely praised for its historical fidelity, particularly its vintage aesthetic and the celebrated Calibre 321 movement, which features a copper-plated finish and column-wheel chronograph mechanism. Owners and reviewers highlight its superb finishing, comfortable bracelet, sharp dial clarity, and superior AR coating, with some considering it the ultimate Speedmaster due to its proportions and hand-finished assembly. The straight-lug case is noted for wearing comfortably and smaller than expected, and the ceramic bezel with white-enamel scale adds durability. However, the Omega Speedmaster Calibre 321 Chronograph 39.7mm comes at a premium price and is criticized for limited availability, a shorter service interval, lack of hacking, and less advanced accuracy compared to the 3861 movement. Some owners express concern about daily wear due to its special nature, while others find it suitable for most activities except swimming.

The Prospex SPEEDTIMER Seiko Brand 100th Anniversary SPEEDTIMER Limited Edition is praised for its retro design, balanced 42mm case, good finishing, and sapphire crystal. It is powered by the calibre 8R48, featuring a column wheel and vertical clutch, and offers 100m water resistance. Some find its 45-hour power reserve short compared to modern alternatives, and the date window placement is a point of discussion. The solar-powered variant is noted for its compact proportions and character, though some desire thinner cases and improved bracelet micro-adjustment. Overall, owners and reviewers appreciate the SPEEDTIMER's vintage-inspired aesthetics and solid build, with critiques focusing on power reserve and minor functional details.