My wife swears by her Packer Plus panniers, and I really like my Back and Front Rollers. There are advantages to both, and both models work very well; it is a matter of personal preference. You cannot float across rivers with the Packer Plus series bags, but during a total of 2 years actually touring with her Ortliebs my wife's gear has never been wet because of the panniers. They have faded but are still waterproof. However, she has not tried swimming across any rivers with them.
She also has a pair of Sport Packer front panniers but she did not use them on this trip.