What is better, QSR or an ultimate
Korg NX5R. (both have the same price)
Some people says:
QSR is old technology, but the sounds are more fat
this is true?

I have both a QS8 and a QSR and they're excellent pieces of equipment. The Ns and the QSs are both romplers. Both allow decent modulation. All I can say is I use my QSs constantly. The sound is great, the control is great. I own lots of Korg gear too but I wouldn't trade my QSs for anything.