The Buffalo was a dog in it's original form. It was designed to operate from US Navy carriers and was overweight and underpowered.
The British used them in the Far East, as Dutch bound planes were diverted to the RAF when The Netherlands fell. Mitsubishi Zeroes made minced meat out of them.
In Finnish service, the heavy stuff was stripped out and thanks to a few modifications, they were actually pretty handy. They gave a good account for themselves against a lot of Soviet aircraft.