First, the Pacific side (west) versus the Gulf (east) side. Generally, this is where most people are heading. In a broad description, the Pacific side is stunning, with more rocks and cliffs, and in some areas, not as “beachy”. In some locations, like Cabo, most of the beaches are not swimmable due to undertow.
The Gulf side has lots and lots of long stretches of beach. There are some areas that are rockier, but still have small beaches.
Both coasts are fantastic, just different. It’s important for you to understand they aren’t the exact same type of experience before you reach a decision on your destination.