Jinhae vs. Masan: Which one is more developed/bustling?

I'm looking for a nearby city to visit for a drive next weekend, but I've already been to most places.
I have exactly two candidates left: Jinhae and Masan. ㅎㅎ I'm not considering anything else besides these two.
I'm planning to go for a drive and visit a downtown or a bustling area to people-watch,
so which of these two cities is more developed?
Also, I'm curious about where I should go to find the most bustling areas in Jinhae and Masan.