I took the Aug MCAT and am applying this year. So far I've gotten interview invitations at 5 out of 10 schools and no acceptances. I missed one interview becuase of a disaster and haven't been able to reschedule, I have 3 waitlists, and I have one up coming interview. I got rejected from my "reach" schools (Penn and U of Chi). I am still waiting for post-secondary news from three schools. I think how much the Aug MCAT hurts you depends on the specific shcools. For example, by the time I got an interview at Loyola, they had already stopped offering acceptances, so I got the best thing possible-- a waitlist spot.
I definately hear carrie's advice. The application cycle is draining. Even though I was in your delemma, I decided that I would "give it a shot" for this year and if things didn't work out, I'd just re-apply, no sweat. But it has taken up quite a bit of time and energy, and at this point I do not know what I will be doing next year, as opposed to knowing I will not be going to med school and being able to more actively pursue other options. Moreover, if I had spent this year pursueing application building experiences, I would have a better shot at a really good school, like UPenn or U of Chi.
On the plus side, I know I will be in school for the next 8 plus years, I'm interested in surgery, so I'm glad I have the chance to start that whole process without delay. I have a real chance at getting in to two of the schools that I'm waitlisted at--they typically have significant movement off of thier waitlists--and I still have a chance at getting in at Finch becuase they are late applicant friendly.
It is a tough decision, and you'll just have to weigh the options yourself. I would say that you should weigh:
a) Do you think you need to improve your application in order to get into the caliber of school that is acceptable to you?
b) How eager are you to get in right away?
I agree that it would be much better to take the MCAT in Aug and have the chance to retake in Apr, rather than take it in Apr and have to retake in Aug. Of course, if you haven't taken an important class, I'd probably wait, unless you feel you can learn the material over the summer.