While the Vehicle Damage Spec would make a difference of one less shot to Destroy, the Vehicle Reload Spec would be far more beneficial from a "utility" perspective.
Both the T90 and Abrams have a four second reload time for their main cannon. The damage from the cannon will take off about 25% of the vehicle's health. V Warhead is 1.25x. V Reload Spec is 0.75x.
With Damage, it would take eight seconds to fire three shells and destroy a vehicle from the front. With Reload, it would take nine seconds to fire four shells and destroy a vehicle from the front.
In a suicidal standstill fight with both vehicles at full health, Damage would win out by one second. With other variables, like an Engineer repairing, long range evasive battles and attacking from the side/rear, Reloading will win.
In any sustained fight where the minimum number of shots is passed, Reloading is superior for the Tank.
As for the Bradley and BMD-3 with the six-shot auto cannons, Damage is better and the Alternate Weapon is better than that.