With the exception of aircraft carriers, Kirov-class battlecruiser are the largest and probably the most powerful surface combatant in the world currently in active service. Iowa-class is believed by most experts as the ultimate battleship, and despite it's age, it had proven itself to be a extremely powerful warship during several post-WWII battle scenarios. If the Iowa-class re-enters service today, and with proper modifications in electronics and weapon systems, it would still be an outstanding ship. Which one of these two ships is more powerful overall? In my opinion, the Iowa has advantage in durability because of its larger displacement. It's actually not a lot bigger than Kirov in term of exterior dimensions, but it has nearly twice the displacement. Which means a big portion of its weight are from the armors. Iowa can definitely take a lot more damage than Kirov I think Kirov has advantage over Iowa in term of firepower because of its large numbers of VLS that can launch large variety of missiles. Iowa may have massive 16-inch guns and has been modified with missile launchers that can launch Tomahawks, but I doubt it can match the firepower of the largest missile cruiser in the world that is equipped with VLS.