Baltic Prismic StonevsSinn U18

Owners and reviewers widely praise the Baltic Prismic Stone for its striking and unique natural stone dials, with specific mentions of the bloodstone and red agate variants being highlights. The watch is noted for its refined, retro dress watch aesthetic, featuring a well-finished 36mm bi-metal case combining stainless steel and titanium, and a slim profile measuring 9.2mm or 9.5mm thick. The hand-wound movement, either an ETA Peseux 7001 or a La Joux-Perret D100, is generally seen as reliable, offering a 42-hour or 50-hour power reserve respectively. However, some owners find the collection overpriced and the small, recessed crown uncomfortable for winding. The Milanese bracelet is also a point of contention, with some finding it may not articulate well for smaller wrists. Accuracy figures vary, with one owner reporting +1/+2 seconds per day and another around -6 seconds per day.

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.