OK (from various sources)...
The F6F Hellcat had the highest Kill/Loss ratio of any American fighter plane in Army, Navy, Marine or Air Force service during WWII.
No fewer than 75 percent of all enemy aircraft in the entire conflict were downed at the hands of Hellcat pilots (EDIT: The F6F accounted for 75% of all aerial victories recorded by the U.S. Navy in the Pacific), credited with some 5,156 total kills in the war for a mind-boggling kill ratio of 19:1. 307 Hellcat pilots were made aces thanks to the fine machine. The aircraft were duly noted for their role in supporting Task Force 58 to which some 400 Japanese aircraft were destroyed in a single week.
Navy and Marine F6Fs flew 66,530 combat sorties (45% of all fighter sorties of the war, 62,386 sorties were flown from aircraft carriers and destroyed 5,163 (56% of all Naval/Marine air victories of the war) at a cost of 270 Hellcats (an overall kill-to-loss ratio of 19:1). The aircraft performed well against the best Japanese opponents with a 13:1 kill ratio against Mitsubishi A6M, 9.5:1 against Nakajima Ki-84, and 3.7:1 against Mitsubishi J2M during the last year of the war. The F6F became the prime ace-maker aircraft in the American inventory, with 305 Hellcat aces.
The Corsair was an extremely impressive aircraft, but all admitted it was unforgiving, and for the cost of two Corsairs the Navy could buy three Hellcats and get them quickly. The Hellcat was much easier to fly, which was far from a trivial consideration when the US was turning out pilots on an assembly line and throwing them into combat, and its availability rate and survivability were outstanding.
In sum, it appears that the Corsair had the edge in sheer capability while the Hellcat had the edge in simple utility. Given that the Hellcat fought in greater numbers, there is no doubt it carried the greater weight in winning the war in the Pacific.
... Still pretty damn impressive.