Just saying, medicine is really rather similar at all unis, you'll get employed no matter where you go. I personally got an A in EPQ and, coming to look at politics at uni, I have some lowered offers (aab-abb etc). EPQ is very respected, in general. More so than sporting activities in clubs.
For me, I didn't work anywhere near enough, it doesn't have to be that much work. To get an A, get friendly with your supervisor, he is your examiner, listen to what he says and follow it like law from the start. If you work hard at the start and prioritise your log you don't have to get an a in your essay, you can comfortably get an a with a b essay if you have a great log.
I would recommed EPQ, but get it done before it gets in the way of your exams and keep on top of it.