Dave G

It depends on how you define "big". Houston is obviously busier, but as I understand it, Brownsville can handle larger ships than the Houston. Aircraft carriers, huge oil drilling ships, etc. If SpaceX decides to assemble BFR cores somewhere along the Brownsville shipping channel, the ability to handle large water vessels is a big plus.

SpaceX installing wick drains at the Boca Chica site:

They have to let the water drain out of the underlying earth first. They're using wick drains for this. This video explains the process:

Note that all of the SpaceX property in the above map was purchased under the name "Dogleg Park, LLC"

If you want accurate...

Why does SpaceX do anything? Why do they build their own stuff in-house? Because they want more control? No. It's all about cost. Building stuff in-house costs less than using traditional suppliers. And for the stuff they do buy from suppliers, this gives them great leverage in negotiating contracts. If the price is too high, they'll build it themselves. Same with their private launch site. SpaceX is betting it will cost significantly less than launching from the cape. You may disagree with SpaceX on this, but you can be sure SpaceX believes it will cost less. And then there's this: AsiaSat CEO says Cape Canaveral has its drawbacks http://www.spaceflightnow.com/falcon9/012/140906capecanaveral/#.VvKAROIrJhE