I say they're a waste. I got all the help I needed from my school's pre-med advisors. Besides, other than getting your personal statements and essays critiqued, its pretty common knowledge that you need to have some EC's that you do because you WANT to, not just because they'll look good, some clinical experience, perhaps some research experience, good grades, and good MCAT scores.
Wow, a med school app in a paragraph! How about that?