It's definitely more intense.
You'll probably have 3 lectures and tutorial/practicals a week. Each day is a new "week"/topic. So if you fall behind, you'll fall behind faster. For me personally though, I found then more intense timing meant I focused a lot more and meant I didn't forget concepts because we learnt them 12 weeks before. You'll also get a week or two break over Christmas and New Year's, but you'll probably have assessments due immediately upon return.
Assignments tend to be the same as a full semester, though occasionally there was a different or easier version of an assignment due to the shorter time frame.
If your not doing anything over summer, it's good. If you want to have a rest or work though it can be difficult to manage.
