@Zambo got it right. The "best" is about being a war-winner. It ain't about the prettiest or even the best dogfighter. Things like range, payload, survivability, and ease of production matter.
Battle of Britain ME-109s barely had enough range for a quick dogfight over Britain before they had to leave or go for a swim in the Channel.
Spits were similarly short-legged. Furthermore, their in-line engines were vulnerable (not very good in the ground-attack role) and they were a b!tch to produce.
The ME 262 was an absolute gamechanger but hampered by range issues.
The Corsair was a badass. Fast and rugged. I love her looks. However, visibility down that looooong nose was terrible. We deemed them unsuitable for carrier work. It was the Brits who figured out a way to land them on carriers (they'd come in on a wide circling approach so the pilot could see the carrier instead of landing blind). The Hellcat had the same engine and better visibility, overall similar performance. I still like the Corsair though.
The Mustang was a war-winner. It was easy to produce. It had immense range. It could do almost everything the other planes could do but had the legs its rivals lacked. It is said that the day Goering looked up into the sky over Berlin and saw Mustangs, he knew the war was over. It did have the weakness of all in-line water-cooled engines...they were vulnerable. If you are talking big picture, it's Mustang.
But...if you want to get into these late variants, I have another name for you.
The Republic P-47 N Thunderbolt.
This fella was produced in numbers and did see action in the Pacific. It was meant to escort the Superfortresses so it was all about range and high altitude performance, but it was still a Jug.
Look at the size of that thing! TWSS
Like the later versions of the Spitfire, they changed the wings (older Jugs had elliptical wings). They jammed fuel everywhere they possibly could (including inside those new wings). The cockpit was considered luxurious. Climate control, roomy enough to stretch out, pressurized, even had an auto-pilot. That stuff matters when you're flying hour after hour after hour over a vast empty ocean. Heavily armed with 8 50 cals in the wings and the ability to carry bombs and rockets. The Jug excelled in the ground-attack role. It was turbosupercharged for high altitude performance, very fast, very high ceiling. Even had a radar in the back to alert the pilot if a bandit got on his tail.
The Jug was legendary for its durability. It's air-cooled radial engine was far more durable than any in-line engine. The plumbing for the turbosupercharger ran under the belly of the plane providing lots of protection for the pilot.
Like most American planes, it was designed for ease of mass production. We cranked out more Jugs than any other American fighter in WWII.
But its ugly.
But can it dogfight.
Blah blah blah.
The BEST is the war winner. This bad boy is just that, a war winner. You can argue that the Tempest was a better ground attack plane and the Typhoon was a better fighter but I'd rather have 2 squadrons of Jugs that can do both jobs well than a squadron of Sturmoviks and a squadron of FW 190s that can only do one job well (and my Jugs can do it all day long while your specialized planes have to land and refuel).
The N model had more range and more firepower and more munitions capacity and a higher ceiling than the P-51. And it was more comfortable to fly and far more survivable.
The N was blazing fast and could always dive itself out of trouble.
So why is the venerable Jug the winner here? It does it all. I can build more of them faster and cheaper than you can build Spits or FWs. When your Spits have to turn around and go home because they're already out of fuel, I have a squadron of Jugs loitering over their base waiting to jump them (or, while your Spits are trying to dogfight, I've got a squadron turning your base into a muddy hole). On the way back, my Jugs will destroy any target of opportunity that presents itself, locomotive, bridge, armored column, fuel depot, whatever, and my Jugs will survive the ground fire and bring my pilots back home alive. My Jugs can perform at low, medium, and high altitude. They can escort Superfortresses. They are excellent at ground attack. They can dogfight. They can go a long, long way.
Wanna know why I don't care what Galland or the Israelis thought? Galland, flying an ME 262, was shot down by a Jug. As for the Israelis, they fought a very specific type of air battle in tiny space. They didn't have to build the planes and they didn't have to fly far or long.
More Information:
Republic P-47N Thunderbolt - War Wings Daily
Performance of the Republic P-47N Thunderbolt:
Performance-wise, the P-47N was a standout in the WWII fighter lineup. The Double Wasp engine enabled a top speed of approximately 467 mph (752 km/h) and a climb rate that was competitive with other high-performance fighters of the era. It had an impressive service ceiling of 43,000 feet (13,106 meters) and a maximum range of about 2,350 miles (3,782 kilometers) with external fuel tanks.
When compared with its contemporaries, the P-47N was unique in its combination of high speed, formidable armament, long range, and ruggedness. It outperformed many fighters in range and payload, though it was generally less agile than smaller fighters like the
P-51 Mustang.
Alex.