KI84, mainly because its the plane I know the best. Its top speed and dive won't outrun many late war planes, but it's climb, acceleration, durability and turning ability make it a good furball survivor.
Its a good vert fighter, but plenty of planes out climb it - Spit 8, 14, 16, LA7, 109G2, G6, G14, K4, etc. It's a great plane if you want to wade into trouble and stay engaged until you or the other guys are dead. If you want to survive by being able to separate and reset, a faster plane would be a better choice.