It looks like you can call down a Titan every 2-3 minutes, so it's kind of like the Titans in UT3, but without having to get kills in first.
I've also seen the trailers where the pilot gets ejected from a destroyed Titan, but he goes straight up before coming back down, so he's a pretty easy target if someone is on the ball to target him.
You can eject out of a titan, fly in to the air then land back on top of another titan and destroy that one

The game is fast paced, addictive and very fun.