This is coolbert:
From a comment to the blog by Steiner:
"I suspect some of the reluctance in the popular mind to admit the superiority of the heavy fighter concept comes from two sources. First, the successful and persistent propaganda campaign of disparagement against the Bf110 during the Battle of Britain, despite the successes of the type as the prototypical strike aircraft during that campaign and as a radar-equipped night fighter in the following years."
That German heavy fighter the Bf110 not performing as hoped during the Battle of Britain, 1940.
The Bf110 as designed by the military planners a heavy fighter plane also able to carry an internal bomb load, able to escort bomber aircraft to the target, almost a jack-of-all-trades. Two-engines, multiple crew, heavy armaments, etc. HEAVY!
HEAVY in the sense also of having a three-man crew. A pilot, radio operator/navigator/bombardier and a rear gunner!
"The Messerschmitt Bf 110 . . . was a twin-engine heavy fighter in the service of the Luftwaffe during World War II."
When arrayed against the Spitfire and Hurricane the Bf110 found lacking, not as fast, not as agile, not as maneuverable inadequate as a "dog fighting" airplane in mortal combat against English adversaries.
"Battle of Britain"
"The Battle of Britain revealed the Bf 110's fatal weaknesses as a daylight fighter against single-engine aircraft."
"A relatively large aircraft, it lacked the agility of the Hurricane and Spitfire and was easily seen. The World War I-era Bristol Fighter had done well with a rear gunner firing a rifle-caliber machine gun, but by World War II, this was insufficient to deter the eight-gun fighters facing the Bf 110. Its size and weight meant that it had high wing loading, which limited its maneuverability. Furthermore, although it had a higher top speed than contemporary RAF Hurricanes, it had poor acceleration."
"The Bf 110 served with success in the early campaigns, the Polish, Norwegian and Battle of France. The Bf 110's lack of agility in the air was its primary weakness. This flaw was exposed during the Battle of Britain, when some Bf 110-equipped units were withdrawn from the battle after very heavy losses and redeployed as night fighters, a role to which the aircraft was well suited."
Heavy losses INDEED! Being shot down faster than they could be replaced.
As with other heavy fighters of the era the Bf110 carrying considerable firepower:
"The Bf 110's main strength was its ability to accept unusually powerful air-to-air weaponry. Early versions had four 7.92 mm (.312 in) MG 17 machine guns in the upper nose and two 20 mm MG FF/M cannons fitted in the lower part of the nose."
"The fighter-bomber versions could carry up to 2,000 kg (4,410 lb) of bombs, depending on the type."
With regard to the Battle of Britain, DEFENSE IS THE STRONGER FORM OF COMBAT! Easier to do and you can accomplish more with less. So it was in 1940 the English able to husband their forces and employ their fighter aircraft in the defensive mode judiciously. ALL advantage to the British and much to the disadvantage of the German attacking Luftwaffe warplanes to include the Bf110.
The Bf110 as a night fighter perhaps without equal, the radar equipped version flown by German aces of which there were MANY! The German night fighter pilots of WW2 as having flown the Bf110 emerging from the war with their honor intact.
That Bf110 a heavy fighter again a niche type aircraft the mission of which was not as originally envisioned.
P.S. Forgot this one. Those British Spitfires during the Battle of Britain had available high octane American AVGAS [aviation gasoline] that WAS NOT obtainable during the Battle of France  just a few months earlier. That added boost of power gave just that right amount of advantage to the defender so that performance of the Spitfire was superior from what was the case only several months earlier.