Widewing,
I have never used the Mk XIV as a turn fighter. I knew before it was added to AH that it was to be used in the vertical and kept fast. That is how I was using it when, thanks to Apple minimizing AH for me to ask if I wanted to update my Apple software, I pancaked it at 400mph.
My issue is just that it made it very hard to do anything with it as it always wanted to fight my control inputs.
I know that fighting a team based, conservative fight the XIV will eat the 84s for lunch, but from a down in the muck, AH brawl standpoint, it seems to me that the Ki-84 is the better fighter. It doesn't fight me. The Mk VIII doesn't fight me either, it just doesn't respond as smoothly as the Ki-84, or so it feels to me.
EDIT:
Also, I have thousands of kills in the Mosquito Mk VI, which is used in similar fashions to the Mk XIV. The Mossie doesn't try to throw me off it's back, so to speak, at every oportunity, even with its weird stalls.