It depends how you ride on public roads. If you crack the throttle open full from every set of lights, slamming it up through the gears, and are worried about saving 50ms on each change, then this is just the mod for you

If you think this will make riding easier by avoiding clutch use in regular day to day riding, then I think you might be dissapointed as quick shifters are intended for track use, where every time you hit the straight you are tucked down behind the fairing, trying to get to the end 0.3sec faster than your rivals. In this case the shifters are pretty good, although in practise you would be clutchless shifting anyway, just backing off the throttle for a faction of a second. How big the fraction is depends on you, and it might be anything from 1/10sec to 1/2sec depending how much practise you've had. The quick shifter simply guarantees it's 50ms or so.
I certainly would not bother for road use, and if you don't already do clutchless changes then I doubt you will ever find a use for one. Try some next time your out, but make sure you don't try it from 1st to 2nd, and make sure the revs are reasonably high.
Cheers,
Jason