What does she want it to do? Is there a place in her current arsenal that she wants it to fit?
I have a pin-down drill which is very smooth and continuous, while I have seen many other people who have ended up with a pin-up drill being long and strong. The Crossroad is very versatile in what it can do based on drilling and surface prep, a little more information about what the ball is going to be meant for will lead to better recomendations.
My Arsenal:
Roto Grip Rogue Cell
900 Global Bounty
Storm CrossRoad
Hammer Blue Vibe