Seems so, their U series gets the submarine steel. The biggest deal for me is temperature resistance, I've had dive watches fail because of lack of it also with this water resistance should be no worries ever. I know Sinn has additional technologies that concern casing of the movement regarding shock resistance but I am unsure if they are in this model, probably do as standard across the range. 

Seiko King Turtle is nice watch to get started, you should try it on tho they are not small. Seiko SPB143 you can find these cheaper and they are really good also. Now couple of divers in i would pick it over Seiko Turtle but not over Seiko Slim turtle, Slim turtle is the Seiko diver I would get right now if I was taking Seiko I only wished it had ceramic bezel. 

Citizen has great entry watches, and also microbrands like Zelos and Monta do to. Christopher ward has great dive watches check them out, I am intending to get one of those in future.

Oris seems nice but a bit vanilla for me. I find their other watches more interesting. Still I havent tried one on a wrist at all, or seen in person.

Sinn EZM3 is absolute unit if you want something that can last apocalypse, I'll be getting this over everything listed here and for sure in future.