The Ki84 really isn't that much more capable than the Nik. The Nik is just a little slower, buttt it can dive way better, so which is more important? The Nik and the Ki84 are extremely close at equal E. It really does come down to the pilot. The high Nik to a low Ki84 is very very dangerous, and a low nik has better defensive measures than the ki84, and can out dive it in case of emergencies at higher alts, is easier to control, and will climb to the KI84 after an over shoot and kill them. Think of diving speed to alt success people use in the MA. Not being able to dive effects a lot of players and their SA, which is why the Ki84 isn't as deadly as people make it out to be. The F4Us can actually get inside both planes on the rolls and during flat turns in a stall fight with full flaps. I've had, and proven, these fights vs really good oponents, it is the reason I fly the F4U more than Ki84s and Niks, it is a better plane period, now the 50 cals don't help as much in quick death shots or rope attempts. I'll say the Ki84 is among the best defenders in the game because of its quick acceleration and roll rate. The Nik is also a better defender than the F4U because of its guns, its quick ability to gain alt over a base, and because the F4Us biggest weak spot is low and slow on the deck, the Jap planes are just a little more versatile low on the deck. For the F4U to be successful it needs 10K (preffered to be higher than all enemies) at least 340 mph, and not get low n slow on the deck. The Nik should fly exactly the same way if you want to be more successful. I'm talking MA here. In the DA or equal co alt speeds, the F4U will beat both of them.
The Nik and the F4U are in a sense, almost identical up to an extent, however, with the F4Us faster speed and better dive, it is highly difficult for the Nik to win. But the thing about Niks is that they are very good in the zoom climb, even better than the ki84 if you ask me. So on the merge you have to break a lot of E to make the fight tight, instead of going for a rope merge against the Nik. The rope merge spells disaster with those large cannons and its ability to climb straight up. You have to be a really good defensive flyer in the Nik. Cmex is a great defensive flyer and gets 85% of his kills making people overshoot and try to rope him in a Nik. The reason is because 95% of the fighters in the MA will catch you.
Personally, I think the Nik is easier to fly and learn than both the Ki84 and F4U. My reasons being that, 1. The Nik is the easiest to control, 2. The Nik can turn well and dive well, this makes it great for attacking fighters at enemy bases. 3. The Nik has much better cannons and allows for quick easy kills. 4. It has a lot of gas. And 5. It's allows newer players to get away with over controlling, much more than the other 2 planes. Although, the Chog is extremely close to the same fighting style, the Chog has slightly better output making it a more capable plane, yet, the F4Us are much more difficult to learn IMHO, because they are not as capable on the deck, where most new players end up fighting most of the time.
