Better is subjective without reams of paper from each manufacturer. The Rolls are a three spool motor and the Pratts two. The Rolls start much faster and emit a cooler "whine" at max blast. Supposedly, they have more oomph at high altitudes, but I never saw it when I was flying both. With the exception of the idiotic Recirc fans and one or two other trivial annoyances, the 57 is a great place to work.