I've known people who go to the college, but I also attend it, and I can't exactly say if it is good or not, because I haven't had experience of many other schools, but I think it is good.
Class sizes depend on the subject, as I've seen some classrooms with 20-ish students, and some with 10-16 students (admittedly, so far those are the language A-Level classes).
Some tutors, I can't speak for all but I assume it is a general thing, do get on your case about attendance and punctuality, and some teachers are more demanding with homework, whilst others are so chill it is like the freaking Arctic. It not only depends on the subject, but on the teacher.
I have gone from being in a school where we were constantly badgered to hand in our homework and study our lives away, so the shock was going to a college in which there wasn't this constantly persistence. Many teachers DO tell you to revise the day's work after school, or do to extra reading on the topic, and blah blah blah, but they it is more of a strong recommendation.
As there are 4 1/2 hours of each subject per week, lessons are split into one 90 minute class, and another 3hr class (but it is 90 mins, a 15 min break, and then 90 mins), but it isn't as much of a drag as it may sound. It isn't 90 minutes of the teacher talking; in some subjects something may randomly provoke a ten minute discussion, or a short video about the topic will be shown, or there will be group work. Teachers DO make an effort to not make it such a boring class so it is much easier to stay alert when what we do changes.
In my experience, the students have been... average, I guess. I have literally been with a friend, and have had her friends come over, and sometimes we would just randomly talk. Half the time I don't know their names, but I've found people aren't always rude and stuff.