Just did this tour the other night. Do not , I repeat, do not walk up to anyone on the street and do the tours. We watched how crowded and miserable people looked on those tours. Take time and book this one out, totally worth it.
Sarah (with an H) was amazing. Engaging and fluid with how she relayed the history. It was more of a conversation than a history lesson. We thoroughly enjoyed her and the tour, are recommending to friends/family visiting.