Kobelco or Komatsu or Volvo Hyundai or size 20 tons

Hello currently the best digger as the most companies turned to a new system depends on the computer, but performance of the operating Azav because the work became difficult as some Al_hussat may hinder the work of the machine previously unknown situation was normal and was the stomach working any now work environment became shops, it is your opinion what is best Kobelco or Komatsu or Volvo Hyundai or size 20 tons