NonCredibleDefense

It supposedly held its own in trials and exercises with other MBTs of the era, and had a marked advantage when defending fixed positions. But it came from an era when effective gun stabilization wasn't really a thing yet (meaning that having to stop to aim wasn't that much of a disadvantage) and the primary threat to tanks was expected to be other tanks (meaning it's light but insanely sloped upper armor would be effective against projectiles on a flat trajectory, rather than a massive liability against top-attack missiles and other modern threats like drones). An excellent outside-the-box design for its era, but not at all suited to the modern battlefield.