Has anyone ever used one on a nc30? are they worth it? Thinking of getting a Rick Oliver kit which uses the standard cables.

I've been using one on my NC30 for the past few years and love it. I found I couldn't easily get to full throttle without either taking another bite at the throttle grip or twisting my wrist around so far that I looked like I had 'issues'

I just fitted my old 675 one to my race NC30.

TBH there are QA throttles and there are QA throttles. A proper one I think would be too hairy on a road bike. Mine has a set of adjustable cams and the biggest I think takes the throw to about 1/7th of a turn.

I find it makes the biggest difference on lefts where I'm hanging off the inside of the bike and find I need to re-grip with a standard throttle tube