I took the kaplan course. The only way it really helped me was to get started long before my test date. If I had it to do over, though, I would do the online course, or just get tough and start studying on my own. I found that a number of people in the class were far from ready to take the test (having only had a few of the necessary science courses), so I spent a lot of wasted time listening to them ask extremely basic questions (what's a benzene?). I'm pretty sure they thought if they spent that much money, kaplan was going to do magic that made them ready in 7 wks.
As long as you take plenty of practice tests, I feel like the thousand dollar course can easily be replaced by the blue book.
I also really liked MCAT audio osmosis for bio, chem, o-chem. Listening to the information a couple times after reading really made it sink in well. It's hokey, but easy to listen to in the car. And days that I was stressed over reading so much, I found I could pop them in the stereo and go over the facts without even realizing I was still studying.