Maybe I'll just get both.
BTW, I'm sort of the opposite of you... the 19 is a perfect fit for my smallish hands. The 17 would have the benefit of greater capacity and a slightly longer sight radius, but I'm not really sure how much of a difference there would be with the two. Maybe I should rent them next time I go to the range.
One of the major pluses of the 19 is I could easily carry it if I wanted to, whereas the 17 would probably be too big. The 19 would probably be pretty good at OWB carry in the winter.