Such a topic is quite interesting...
In my oppinion one of the best fighters of ww2, if not the best, was the Messerschmidt Me-109/Bf-109. It could manouver better then it's allied counterparts both the Spitfire and the Mustang...It's only weak point was it's visibility...the cockpit was a bit crowded and the glass didn't permit a very good FOV...But once the pilot spotted the enemy it was all most certain who the victor would be... The Spitfire was one of the most elegant...if you would allow me the oppinion...I am a Spitfire fan...but it had a weak engine, and it was easelly surpassed by it's german counterpart... I may be wrong but if the Luftwaffe would have managed their resources more effectively the ww2 sky would not have been taken from them... Their air supremacy would have lasted till the end of the war...and probablly many more years from then on...