It is extremely head heavy which gives some pretty crazy smashes BUT without the user friendly Yonex shaft. The VTZF becomes fairly unstable after you hit a huge smash because the shaft is not very sturdy. The MX JJS on the other hand feels sturdy and not too stiff (compared with MX80).
Will definitely recommend this racket for those looking for a more singles oriented racket. For doubles, stick with the MX80.