While this second Defense Tower works the same as the first, and does not have a larger area of effect (that is, it protects the same sized area of land as your first tower), it does add another activation slot to the feature, allowing you to keep these towers active for up to 32 hours.
Remember, even though these Defense Towers protect some of your buildings (hopefully you've placed them near your most important structures that would give your enemies the most resources if stormed), you can still Invade other empires at will. You'll just need to keep supplying your towers with energy drinks to keep them moving.
If this feature goes over well, or as our empires continue to grow in terms of land size, it's presumable that Zynga will add more Defense Towers to the game's lineup, and we'll make sure to let you know if they do.
Are you a fan of the Defense Tower feature in Empires & Allies, or do you think it tips the "fairness" scale towards those who can afford to supply the energy drinks to keep the towers going? Sound off in the comments.