It's a really close call for me, but I think I might stick to the AirPods 2 because of their price and their small size, which allow me to carry them wherever I go.
If I had unlimited funds, I would probably keep both, and use the PowerBeats Pro at the gym and when I'm running, and the AirPods at work and when I go out.
I also have a pair of over-ear headphones, the Bose QC35 II, that I use whenever I want to shut the whole world out, for example on flights.
Some other good alternatives I might consider are the Bose SoundSport Free and the Jabra Elite 65T. Don't hesitate to create a new showdown (or edit this one)
if you've tried any of them, and want to show us how they compare!