What is the Difference between JG ( Jing Gong ) and Tokyo Mauri?

I own an airsoft rifle from JG ( a sig 552 ) I really like how the gun looks and it performs very well. I got the gun for over 100 dollars and I see my gun from Tokyo Mauri for 2-3 times as much. The package my gun came with states that it is the exact replica as the Tokyo Mauri. Why is there such a huge price difference? Is it the materials used to construct the gun, is it a different type of gear box/ motor. Is it just how popular and well known Tokyo Mauri is?