Got my KZ-PR1 Pro yesterday night (Canada Post works day and night, I am happy to admit that I was wrong about them).
PR1 Pro is great, and for $42 - just amazing/fantastic (finally, it pays off a bit to be a KZ beta/gamma tester
)
I liked PR1 HiFi, but the drone bass made them a bit of a special flavour IEM for me.
PR1 Pro perfectly fixed the bass, near ideal to my preferences - it is mightily there when needed, perfect!
Mids feel a bit more defined in the refined, more mature tuning, super great for KZ!
The treble is still there mightily. Many/most may opt to use good-quality foams provided. Me, happy with this treble, true, a bit hot, but for most of classical music recordings it works very well to my ears, and it is always easy to trim than to add.
Finally, I love the build quality, how quite large planar driver made to fit snugly to fairly compact shell. The transparent plastic is more aesthetically pleasing and more practical in cold Canadian winters than metal-plated plastic. All 7 magnet strips can be nicely seen.
Great job, KZ in redefining ChiFi standards, yet another time!