Bremont Supermarine 500MvsSinn U18

Owners widely praise the Bremont Supermarine 500M's luxurious appearance and sapphire bezel, with some preferring its design over other luxury dive watches. Reviewers note its updated, legible dial with excellent, long-lasting Super-LumiNova lume. The hardened steel case with anti-reflective coating offers scratch resistance, and the crown placement is a favored feature. Some owners find the 43mm thickness substantial, and one reviewer questions the long-term water resistance of its three-piece case construction compared to traditional designs. Criticisms include the lack of a dive suit extension on the bracelet and a second hand that can be difficult to see in low light, with some finding the bezel markings could be more prominent. Overall, owners and reviewers consider the Bremont Supermarine 500M a handsome, rugged dive watch with a refined look that competes well with more expensive brands.

The Sinn U18 is praised for its unique deep blue/green dial with three-dimensional oxygen bubbles that change with light, and its comfortable, easily adjustable bracelet. Owners find the watch stunning and a piece of history, appreciating the refined hands. The Sinn U18 features a 44mm, 15.5mm thick case made from German submarine steel, offering a 2000-meter dive specification and Sinn's Ar-Dehumidifying technology, powered by a Sellita SW300-1 movement. The case thickness is apparent, and the watch comes as a complete set with box and papers for $3,000-$3,680. On balance, owners and reviewers rate the Sinn U18 highly for its striking dial and robust build.