What is a better beach experience for a family? South Padre Or Port Aransas?

I am taking my wife and 7 year old daughter to texas at the end of march for a little vacation. While we are there we wanted to spend 1 day at the beach. Ive heard that Port Aransas smells bad and the beach is full of seaweed etc...South Padre looked great but I have a couple issues with it. #1 is Padre island worth an extra 2 hours drive? And #2 is Padre gonna be any kind of place to have my 7 year old in the last week of march? I know its a hot spot for Spring Break and dont really want my girl getting puked on by some college kid. Please can some texans let me know what to do here?