Key Point: Don't crown this tank the best of the best just yet.
The Merkava tank is sometimes called the most survivable tank in the world. The reasons given usually include its active protection system, forward engine design, urban warfare specific modifications, and thick armor. But do these claims hold up to scrutiny?
The Merkava was designed in the 1970s following the failure to purchase Chieftain tanks from the United Kingdom. Originally designed to duke it out with Soviet tanks in the deserts surrounding Israel, the tank was laid out in a rather unorthodox manner compared to contemporary Western and Soviet tanks, featuring a design more akin to some infantry fighting vehicles. Instead of having the engine at the rear, the engine was moved in front of the crew compartment, with the turret placed further back on the chassis.
The result was that the front armor could be more gradually sloped, and the crew could enter and exit the tank quickly from the rear.
However, this comes with the drawback of having the engine more easily disabled, as any penetrating front hit will disable it. Israeli doctrine prioritizes the survivability of the crew in an engagement, so in the event of a disabling hit the crew will bail out rapidly through the rear hatch if the situation allows. On the other hand, a penetrating frontal hit on a western tank will likely leave the tank still mobile.
While the question of whether a tank crew would stay in a tank or not after a penetrating hit is up for a lot of debate, there are instances where mobility will increase the survivability of the crew, primarily in a fighting disengagement where the tank might be surrounded. In an engagement where an attack is succeeding (which to be fair to the Israeli Defense Forces, is likely in most of their post-1970s conflicts), the Merkava’s design makes sense, but for a European army expecting to hold against a Soviet or later a Russian advance, a mobility kill might be a far bigger deal.