Stephanie,
There are two sides to this story. Yes, the summer course is a good building block for class, but you WILL review everything you do in the summer in class during the year. Yes, biochem is difficult, but Immuno was the worst and that's not covered in the summer. The summer course (last summer) was basic biochem. I noticed that people who took the class went to lecture less and spent more time studying b/c it's the SAME EXACT lecture during the year as the summer...
On the flip side, is my reason for not taking it. It costs money and I wanted to enjoy every minute of my summer. Yes, the course gives you a jump, but it takes weeks off the summer (when you could be earning money or having fun or both).
So, add up what's important to you. If you want the head start, do it. I didn't hear anyone who took it say that they wish they hadn't. Oh, and just to know, those people that do poorly in the basic sciences first year are encouraged to take the summer course with the first years to review. So, I guess that says something about the usefullness of it all too.
If you have more questions, email me.
Michelle