I´ve been using the Bmai fly (jingtang). Picked up for US90 on august.
Feels great for me, at 3'50''/4'15''xkm.
Don´t know for faster rithms because I can´t :'(
But for slower like 5'30''xkm, I don´t like them, I feel like the heel is too squishy and I can´t sit on my hips to run slow.
For the record, I have used Saucony Endorphin pro 3, Nike Alphafly 1, and still using Asics Metaspeed sky.
I weight 73kg