RE: P-51MUSTANG RCU.COM
When the Fw 190 entered the war, there was no allied plane that could compete with it. The Brits even said so and thus hastened production of later versions of the Spitty.
The ONLY reason the Me-262 was an operational nightmare was because it was not put into service when it could have been, and there was a lack of proper training and the supplies of good alloys were gone due to Allied bombing. Had the Me-262 entered combat when it was supposed to, it would have been big trouble for the Allies. The P-80 would have been no challenge to the Me-262 until its later revisions which showed up around 1948-49, and the Meteor was next to useless as a gun platfrom until the F8 was release (for various reasons, including a horrible canopy, ineffective rudders & alierons, snaking and other such stuff).
Again, until Allied bombing started damaging German's war industry, the Allies were well behind the 8-ball.
Tanks, large caliber weapons, rocket weapons, machine guns, aircraft were all ahead of where the Allies were.