Citizen Eco-Drive OnevsFormex Reef 39.5 mm

The Citizen Eco-Drive One is widely celebrated for its groundbreaking thinness, with multiple sources confirming its status as the world's thinnest light-powered watch, measuring between 2.98mm and 3.5mm. Owners and reviewers alike praise its exceptional lightness, titanium construction, and good build quality that avoids feeling flimsy, noting its "wow factor" and superb finishing. The watch features a proprietary, ultra-thin Eco-Drive quartz movement and a synthetic sapphire dial, with some models offering up to 12 months of power reserve. However, its high price, ranging from $3,500 to $5,000, is a significant drawback for some, and its aesthetic is considered too plain or dated by a minority who prefer other Citizen models. The Citizen Eco-Drive One is also noted for lacking a seconds hand and having only splash-resistant water protection.

The Formex Reef 39.5 mm is widely praised for its refined finishing, comfortable and well-proportioned case design, and impressive specifications for its price point, including COSC-certified Sellita SW300-1 movement and 300m water resistance. Owners and reviewers highlight the tool-less micro-adjust clasp and quick-release spring bars as practical features. Some reviewers note that the 22mm lug width feels slightly disproportionate to the smaller case, and the bracelet could benefit from more taper, though this is a point of contention for some owners who value the overall package. A prototype crown protrusion issue is noted as being addressed for production. On balance, owners and reviewers rate the Formex Reef 39.5 mm highly for its excellent value and well-executed design.