One Prof give me an advice that I should choose a Department where I feel interested in research of three Profs or at least 2 Profs. It meant that I will be more safe at this Program.
However In your case, you should find more information about the Profs and his group at the first school, especially the relationship between he and his students,... (from some of his students, or some students in this department,.....). If the information is positive, you should go the first school. And if you get some bad new, you can choose the second one.
Good luck to you.