Apple’s iPhone 15 vs iPhone 15 Plus: Which one should you get?

Apple just announced the 2023 iPhone lineup, once again consisting of four different models. There are two base phones in the iPhone 15 and iPhone 15 Plus, and two premium models in the iPhone 15 Pro and 15 Pro Max. If you have your eye on the iPhone 15 or iPhone 15 Plus, it can be hard to decide. They look very much alike, only one is bigger. But what else is different? Is there anything unique about the bigger one? What about the smaller one?