High school seems allot more laid back then middle school with not as many rules and teachers that don't hover over your shoulder as you work. It also seems that there's not that much homework but that might just be me but I'm not complaining. In my old school they like to start you out with lots of work and projects in the beginning of the year to see what you can do. They seem to lay off of dress code in high school more as well.
The teachers are allot more laid back and not as strict on policy. Yet with more self timed projects and procrastination on the rampage high school can be more stressing then middle school as well and it can be more tiring knowing that all of your grades will be seen by anyone you try and get a job from at any time.
You have your pros and cons for everything including high school and middle school they can both be challenging at times but fun at others just try and look and the pros and power through.