I also believe that the SpitVIII is more stable when flirting with a stall, and noticeably less prone to the hated snap-stall into a flat spin routine. The SpitVIII also turns smaller, quicker circles than the SpitXVI. That said, the SpitXVI's ability to change lift vectors much faster than the Mk.VIII gives it the better chance for a killing shot before stability enters the equation.
Either one is a killer...
My regards,
Widewing