I have noticed three obvious differences between life as a teacher in middle school versus elementary school.
The length of time a teacher has with the students is inflexible. That difference is going to play a huge factor in the instruction. I cannot adjust my schedule to increase or decrease the amount of attention I give a concept or subject when necessary.
I have time to prepare. I am sure that as time goes on, it will be spent furiously grading papers. I believe strongly in feedback to the students, and returning quizzes promptly graded is important, especially to those interested in learning from their mistakes. However, I will have that "prep" time to do it. Elementary teachers, at least in my school district, have very little "prep" time (free time) to grade , plan, or prepare.