Kings or Queens?Watch
It doesn't matter where you do Medicine. As long as you got into the course be happy. I'll say Queen Mary is just a bit more reputable than King's for Medicine because of their Barts and London Medical School which is world class but that doesn't really matter to be honest. Queen Mary might offer you cheaper accommodation. If that's the case then choose Queen Mary. The only things King's has advantage over Queen Mary is location; King's is in Central London while Queen Mary is in East London.