Overly fragile, overly hard to aim with, not a great turn fighter and has a horrid 3 to 1 cooldown to WEP ratio.
And people kept telling me I was nuts to argue it shouldn't be perked, saying it would dominate the MA if the perk was removed. Turns out that what I, and others such as Luche, said would happen is exactly what happened.
EDIT:
It's fairly slow for a late war plane at the typical MA altitudes(Spit16 is faster below 10k). Its also the corkiest and least stable spitfire with its huge increase in torque and the fact that the prop spins in the opposite direction.
Not sure which Spits you've been flying, but the XVI is not faster than the XIV at any altitude. Does turn and roll a lot better though. Better gunnery platform too.