The Executor is a cool ship and all, but I prefer Darth Nihilus's ship more. It just feels more of a living creature instead of a ship. It has been in battle before, and instead of technology that's keeping the ship intact, its the force. And as Vader says:
''The ability to destroy a planet is insignificant next to the power of the Force.''
However, what is curious is that if the Exile and the Mandalorions still planted those minds but never faced Nihlius, would the ship still be in operation? Because, I've read on this topic before and somebody said that Nihlius needs to be destroyed in order to blow up his ship.