Dorothy Sayers starter

If I were to introduce someone to the Lord Peter Whimsey stories, what is the best one to start with?
The two nominations in my head are "Whose Body?" and "Strong Poison". WB because it is the first, sets the stage well, and has the I think very important scene where Peter's PTSD shows through. On the other hand, Strong Poison is the start of the Harriet stories, which many people prefer.