Classroom is much more interactive for students. They can complete assignments & turn them in whereas on Sites it appears that they can more so only view the information posted.
Classroom is better for communication. Students can comment back and we can have conversations surrounding their work (either individually in private comments or about whole class questions in the stream). Sites does not appear to allow for that type of communication.
Classroom allows students to get feedback (including comments and scores) on their grades. Sites does not appear to have that type of feedback for students.
