Bentley vs Head Royce for middle school

Can anyone meaningfully comment on their experience with middle school at Bentley vs Head Royce? Difference in philosophy and teaching styles, quality of teachers, amount of homework, demographics of students in the classes? What percentage of the students go on to the upper school? Looking for an emphasis on collaborative learning, problem solving and critical thinking, ability to fast track in math, service learning opportunities/connections with the real world outside of school and mindful use of technology.  Also, which is more manageable for someone with a busy extracurricular schedule? Thanks in advance!