For a brief period, I owned both the Stowa Marine Automatic and the Steinhart Marine 38, so I thought I should get some pics of them together and give my thoughts on each. I bought the Steinhart new and ended up selling it to obi1jabroni from this forum when the Stowa with the exact specifications I wanted came up on the used market. This isn't a perfect comparison since it's the Stowa without date.
When the Stowa first arrived, I thought I might have made a mistake because, in dimmer indoor lighting, the dial appears boring next to the Steinhart. The Stowa silver dial looks very plain without good lighting. The Steinhart's pearl white dial still shines, and the raised numbers and engraved logo make it stand out.
However, under direct sunlight the Stowa dial really sparkles in a way that can't be captured in a photo, while the Steinhart can get too shiny. The Stowa has heat-tempered blue hands rather than the chemically induced on the Steinhart, and I do like the bluest angle of the Stowa better than the Steinhart. Straight on they look similar. I wasn't sure if I would like the blue crown on the Steinhart but I did, as well as the blue rotor which I felt dressed up the movement, though the Stowa movement (which is the same movement) has an advantage with its blued screws.
The case and strap on the Stowa feels much more natural to me, the biggest reason I'm pleased to have gotten the Stowa. At 13mm, I think the Steinhart's case is too thick for a 38mm watch. The Stowa at 40mm and 10.4mm sits better on the wrist for me and the strap is so comfortable. The Steinhart strap and deployment clasp looks great but felt very stiff to me.
In conclusion, for half the price with the same movement, I think the Steinhart is a good deal and has some advantages over the Stowa. I favor the Stowa mostly for feel. Perhaps others would find the Steinhart more comfortable. It's important to me how a watch feels on the wrist. That's why I spent more than twice as much to get an Oris Artelier Date over a Hamilton Jazzmaster Viewmatic when I tried them both on, and that's why I know I would have shelled out more for the Stowa over the Steinhart if I could have tried them both on before buying. If I could, I would take the Steinhart dial, Stowa case, Stowa hands, Stowa blued screws and Stowa strap. But the hands and screws aren't that big of a deal. What it boils down to is if the Steinhart had the Stowa case, I would take it and save the money.