Does local law allow for a choice of governing law?
Frequency/market practice: Yes.
What is the common governing law?
Frequency/market practice: It is common to choose Spanish law if the target is in Spain.
Is litigation or arbitration more common? If arbitration, where?
Frequency/market practice: Arbitration is more common. International Chamber of Commerce arbitration in London or Paris or arbitration administered by a Spanish arbitral body in a Spanish venue is common.