The Vostok Amphibia is an iconic watch with a cult following, but a lot of people who buy them end up disappointed.
To appreciate a Vostok, or really any Russian watch, you have to be prepared for something quite different to what you get from the Swiss, Germans and Japanese. Russian watchmaking, like the sterotype of most Russian engineering, is about simplicity in manufacture, simplicity in maintenance, and incorporating technology only where necessary. Refinement and technological excellence really don't come into it. Think of them like a Soviet tank or the AK-47.
A lot of people assume, because of the price and the cult following, that an Amphibia will be like a Seiko but with a quirky visual design. That's not really the case at all.
To begin with, the core physical design of the Amphibia hasn't changed much since it was first developed in 1967. The aim was to create a Soviet-produced 200m dive watch for the Soviet military. The Swiss were achieving 200m through manufacturing cases and casebacks to very tight tolerances; the existing Soviet watch factories could not match that precision, and could not afford to re-tool in order to. This constraint led to some innovative design choices that are at the core of the Amphibia.
The first is the caseback. A traditional screw-down caseback has an o-ring seated in the thread. When tightening the caseback, this o-ring is squashed into the thread, creating a watertight seal. The o-ring has to be fairly thin, and the tortional force of screwing in the caseback distorts it, meaning that it has to be replaced regularly.
The Amphibia's back, however, is held by a screw-in retaining ring, which pushes the back onto a thick gasket. The genius of this design is that under higher pressure, the caseback gets pushed harder into the gasket, creating a stronger seal. The gasket also has a much longer lifespan.
It's a similar story with the crystal. The engineers found an acrylic that has just the right properties under pressure that cause it to distort and push into the case, increasing water resistence, while being firm enough to provide protection under lower pressure.
The other noticably quirky design is the crown, which people often think is broken when they first use it. Unlike a traditional design where the crown is always coupled to the stem, the Amphibia has a clutch mechanism. This means that, when screwed in, any shocks to the crown are not directly transfered to the centre of the movement. This is why the more traditional case designs did not need to incorporate crown guards.
So that's some of what makes the Vostok cool. What may let you down is the simple case finishing, the bracelets (which are complete garbage) and the bi-directional friction bezel. The bezel in particular gets people's knickers in a knot, because we all "know" that a dive watch must have a uni-directional click bezel. Back in the 60s though, Blancpain held the patent to that technology, and almost all dive watches used a bi-directional friction bezel. And remember, the Amphibia design has not changed in 50 years.
While we're talking about bezels, you'll rarely see a Vostok in the wild with the bezel that came from the factory. That's because, for the most part, they're pretty ugly, and replacing them is a really simple and relatively cheap way to customise your watch.
Likewise, the movement is designed for robustness and servicability, not accuracy or looks. From the factory, it's likely that the watch will run 20-60s/d fast, but with some simple DIY regulating it's easy to get them to about +5.
So if you like quirky, practical, historically significant design that hasn't really changed in 50 years, an Amphibia might be for you. If you want something that's well finished, cheap and robust, get a Seiko or an Orient :)