What is the best tank Challenger 2 or Abrams M1A2?

Opinions will always vary, and are dependent upon the test conditions provided.

Over 10k Abrams have been built,and over 8k currently serve with the USMC and US Army.

Only 450 Challenger 2 tanks are in service with the British Army.

The M1 has the best combat record of any modern main battle tank,in the World today.Thats a true story.M1s have been lost,but M1s have made scrap yards out of other nations tanks.Sure,this was against inferior tanks,but it still got the job done,and a M1 has never been destroyed by another tank.Insurgants and road sides bombs have destroyed M1s,though.