I'm flexible with aisle/window, but if the aisle is taken in row 17 I won't sit there. The windows, 17A and 17F, have a "built-in" armrest on the exit door itself which is about the size of a roll of quarters and therefore useless. Also there's a sign stating that the window seat headrest flaps do not adjust, which is accurate.

With all those minor annoyances I'll take PC if the aisle exit rows are full.