This is really two issues. Advantages of each have been covered above, but if your engine is stock then the extra grip of the Dali clutch is less significant than the fact that it's also cheaper than new. (It's a rebuilt OEM unit).
I see no reason why the stock flywheel needs to be replaced just because you replace the clutch (assuming the new clutch is designed to fit the stock flywheel of course.) I have owned and worked on numerous cars and never had to do more than re-surface a flywheel, just as you do a brake rotor. Unless the factory manual says otherwise, don't get talked into it. On the other hand, I wouldn't go to the trouble to replace the clutch without changing to the lighter flywheel while I'm at it. The price is not too obscene.
Do keep in mind that people who already have trouble taking off smoothly with a stock flywheel/clutch (in good shape) may not be happy with either a stiffer (more abrupt) clutch or the lighter flywheel. Both require more finesse when driving the SO or Mom around.
BTW, I've ordered both from Dali and will do them some rainy weekend this summer.