From an editor, here’s a well-thought-out post on the pros and cons of prologues from a contemporary point of view. It starts with the pros. which, if you have used one, you already know. Keep reading. You may need yours, but you do need to know why they are less common in contemporary fiction than in works written 30, 40, 0r 50 years ago.
Good sense about prologues from author and former agent Nathan Bransford.