I knew my ears weren't deceiving me. The distortion in the JBL 306P's and in the original 305's is extremely noticeable. Not so much if it is your first ever decent speaker, but when faced against other speakers in a similar class with considerably less distortion the muddiness leaks through, even when used with advanced room correction like DIRAC.
I've compared the 306P's to Emotiva Airmotiv 5S and Adam T5V's, and in both cases the JBL's lose. The much smaller 5" speakers get much louder, much cleaner and sound less boxy in the mid-field. The transparency is also on another level. Those are speakers you could use in a living room, whereas the JBL's must be regulated to a desk.
Sad thing is Harman could make the JBL 3XXP's so much better than they are without a price hike. It's like they intentionally neutered them so they wouldn't step on the toes of their more expensive offerings, at the same time making them just good enough for mass appeal.
I paid $160 for my 306P's brand new, which was a steal. At MSRP I would steer clear.