Thermage Nxt or Cpt?

I am 35 looking to achieve a more contoured and tightened look using non invasive procedures. My derm pushed me towards Thermage The confusion is whether I should choose the Cpt or Nxt as I have been told that the efficacy levels of both the devices are same except that Cpt provides vibrations to enhance comfort. But the both devices are equally effective. In terms of SAFETY PROFILE and EFFICACY, which device would you suggest ? Thank you!