Hello everybody! I’ve got accepted to Business, Competition and Regulatory Master Program(Freie Universitat zu Berlin) and Advanced International and European Business Law Master Program(Leiden University). Which one should I opt for and why? Thank you

These are both world-class institutions. Leiden may have the edge in terms of visibility / recognition, since it's a bigger school with a much bigger alumni base, but this may vary depending on the organizations in your country.

If I were you I would go through each program's course offerings and faculty, to see which appeals to you the most.