Funny, just had that conversation with an instructor. He insisted that .38 special was the best choice for personal protection, but informed me that 9mm was a poor choice (with a sad look on his face).
Of course, most of his research was done many years ago...good at teaching fundamentals and got the class of non-shooters to pretty good performance, but very opinionated about old data. I left him a 9mm Gold Dot for his show and tell about caliber and ammunition selection.
