I have a driftmotion lightweight flywheel. I've used it with both a Clutchmasters FX400 ceramic/puck/sprung clutch, and also the driftmotion stage don't-remember that is also a ceramic puck clutch.
I have a stock head/cams with an old Master Power 72 turbo.
I also have an all-stock IS300 with W55 for comparison, final gearing is same for both cars.
Anyway, you can definitely feel the lack of rotational inertia getting the car going from a stop. It wouldn't be "bad" if not for the ceramic puck clutch disk that doesn't like to slip. There is a learning curve to giving the throttle a blip, and quickly beginning to engage the clutch. Done properly, the whole thing can be done gently and smoothly. In the hands of a noob or a typical girlfriend, there will be lots of clutch chatter and stalling.
I've driven all sorts of manual transmissions for 20+ years, and the light wheel + ceramic puck clutch combination was almost like starting over.
At first I was being too gentle and getting terrible clutch chatter. Then I realized that over ~1500rpm or so, slipping the clutch doesn't chatter - so I would rev it up and engage the clutch smoothly (but too slowly). With practice, I've gotten the feel for it so that I can give just the blip in combination with a fairly aggressive engagement. Again, when done properly after practice, this can be very smoothly with no chatter, no tire chirp, no lurching of the car. Getting started on a hill will require a more aggressive throttle blip and a slower, gentler clutch engagement. But that, too, can be done smoothly without chatter/chirping/lurching.
Last, what Piggity said above about low rpm transmission clatter on account of the light flywheel is totally true.
