The newly released 2018 Omega Seamaster 300 Professional gets my pick for this category. The price for the watch with rubber is just below $5,000.

Having tried this on in person and I can honestly say, despite my antagonism towards Omega for the price increase, it did not surprise me as the watch is a steal even with the newly increased prices. To start with, it has 300 meters of water resistance so you can definitely go to the beach or snorkel with it no problem, although I have not seen many leather straps worn with this watch yet online, I can totally see this paired up with a nice leather strap for the daily desk diving or a nice dinner.
A bit more details about the watch, whereas previously the watch had a date window at 3 o’clock, the new version moved it to 6 o’clock, creating a nice symmetry on the beautiful ceramic dial.

I personally would choose the blue simply due to how dynamic it is, and if I ever became a one watch guy, I’ll take the black dial for the versatility with wardrobe selection, but save that for another day.
For watches at this price range, the case construction should be discussed as the side case is brushed while the lugs are polished on the outer side with the inner edges brushed offering a very luxurious feel. Beating inside is the Omega caliberCaliber The caliber ('movement') is the heart and engine of a watch. It consists of a number of interconnected components that work together. Energy is transmitted through the gear train, to the escapement mechanism. The escapement mechanism releases this energy in a controlled manner. This drives the gear train, which ultimately rotates the hands of the watch and keeps time. [More Info] 8800 with 55 hours of power reserveRéserve de marche Also known as Power Reserve. A watch's power reserve refers to the amount of time a mechanical watch can run without being wound. The power reserve of a mechanical watch can vary depending on the size of the mainspring, the efficiency of the gear train, and the rate at which the mainspring releases energy. If a watch has a Power Reserve 'complication' it simply means that the status of the power reserve can be seen on the watch itself (either on the dial or movement side of the watch). [Learn More] and is magnetic resistant up to 15,000 Gauss, so anything short of an MRI scan you should be fine as far as having your movement magnetized.

In addition, the new movement also allows the watch to be thinner, now standing at 13.5mm tall, which should fit perfectly under the cuff.
Runners Up
There were a few other watches I liked, namely the Omega Railmaster and Tudor Black Bay Bronze.

While the Railmaster offered a lot of what a GADA watch entails, it just felt a bit short when comparing it to the Seamaster as they have the exact same price. The Seamaster has a nice ceramic dial with applied indexes while the Railmaster has painted lume markers and no display caseback to show off that nicely decorated movement.

The Black Bay Bronze was a contender as well at $4,050 with the new slate grey dial and said bronze case. However, the watch is slightly bigger in both case diameter and thickness at 43mm and 14.8mm tall.
The side case is brushed with a nice touch of polished beveling, however, after trying this in person the case size and the bronze case prevented it as the winner for this category.
Seamaster images courtesy Omegawatches.
The new Seamaster 300 Professional in white is absolutely stunning!