I'm going to join in here as I've just got a pair of these on Friday. DUNU has done a great job on these! I haven't had a whole lot of time with them just yet and don't want to jump the gun but they do sound like something very special. One thing I do want to state though: "DAT BASS YO!"
G*d damn, the quality of the bass is great. Maybe just a little slower than some TOTL IEMs but the quantity makes up for that with great rumble and visceral punch. Very fun to listen to and feels like I've got subwoofers in my ears.
I've not A-B'ed them yet, from first impressions of the DK-3001, The FLC8S has better imaging and detail retrieval, as well as the FLC8 can be customised with it's sound signature. Where the biggest difference lies is the bass response of the DK-3001 is much more tuned for enjoyment rather than critical listening. The FLC8, even with the red and black bas filters (the most bassy setup), doesn't have nearly as much quantity of bass, however, it's speed is much better. Also, the DK-3001 goes lower and louder in those ultralow frequencies under 100Hz. The FLC8 is still an awesome choice is you want a very details and flat to bright sound signature, but you'd like it to be more flexible if you get bored of a particular sound.