First, I've been flying the ki-84 almost exclusively since it came out and I like it. However...
It turns like crap until you get very very slow and can deploy flaps. That means that most players will never "get the hang of" flying it. It isn't fast enough, a good enough climber, or hard hitting enough to excel as a BnZ platform, it's not as damage resistant as comparable US or german aircraft either. It's poor pitch response at higher speeds also means it must be constantly trimmed to get maximum performance out of it. With combat trim or "easy mode" turned on, it's very hard to get the plane slow enough and trimmed properly to turn well.
But if you learn how to fly it, it's a good all-around dogfighter and a talented player can even beat a well flown spit unless the fight degenerates into a simple flat turn rate contest on the deck. It also has a decent roll rate across the entire speed range which helps against USN rides.
