Well, only you can answer that question really as power from rackets is a very subjective thing. Personally, I think the Arc10 provides better control but you could find otherwise.
I have them both... I like the NS8000 more than Arc10 because it can move faster since its headlight-ness. However, I'm not saying Arc10 is bad. Arc10 is considered as a all-round which defense=offense. To my preference, how much power and control you can produce with a racquet also depends on your skills, the string you use, and the string tension you choose. Also to note is that the way you smash. Do you use more arm power or more wrist flex? That would contribute to the effectiveness use of a racquet too.
I find that when you try to do a hard smash with wrist flex, Arc10 has less output of power compared with NS8000. So in order to counter that effect, I add more arm power (like swing my arm harder) and smash seems to be faster and harder. However, that's just me. Best is to try smashing continuously until you find the right "feel" to your Arc10.
