They should actually be pretty comparable. The difference is some people say the Quart tweeters are harsh, although IMO they're extremely detailed on certain things. Never heard too many tweeters that'll make the sound of glass shattering like those things.
I run the PSD316 and am aware of the harshness that every is speaking of. However, I noticed if processed and crossover correctly they will in fact be very well detailed and smooth. It does not take much to get them bright but, the new silk dome although pleasant to listen too some how does not seem as accurate in some music applications.