A friend told me JBL DD67000 is actually very bad speaker, is it true?

Your friend highlights the gulf between differing persons' preferences in this hobby. It should be pretty obvious that as there are many different tastes in music, so also there are many different tastes in music reproduction for the home. There are sizable variances in how transducers produce sound, and the discerning audiophile will recognize that. To simply condemn certain types of speakers as no good is grossly ignorant ( I suspect your friend is actually stating his preferences strongly). You will want to find your optimum sound and then naturally will feel these genre of speakers are superior. But, be prepared as many will sense just the opposite. You will find that things such as imaging, tonality, coloration degree from cabinet contribution, etc. will become very important to you as well if you delve into the hobby deeper. 

I tend to enjoy speakers with less perceived cabinet contribution, and spend quite a bit of time with panel speakers for that reason. However, I can appreciate why many adore speakers with cabinet contribution. It's a classic case of YMMV. 

What Douglas said, + 1.

coli, as you can glean from other posts of mine on this forum I am and always have been a big fan of JBL. Terrific sounding speakers in general and of course some models better than others. That said, I wouldn’t go as far as to say "their newest designs are the best value in audio right now, nothing comes even close" Consider a pair of GoldenEar Triton 1. In my view the T1s are a far better value. JBL cannot compete at a $5K price point. Higher end JBLs are phenomenal, but you pay for it dearly with big $$$$. (hence the reason "best value" can be scrutinized) 

If you can afford to purchase  the 67000 then you can afford to go demo them at some point.  If you are spending that kind of cash, then you certainly should audition and see what you like.

I have the S3900's and they image like crazy, but what I really like is that instruments, particularly guitars, drums and vocals sound real.  I also prefer rock music and the JBL's do it justice.  Dynamic without being bright and just a bit midrange forward.

I can also appreciate a great panel speaker.  I've demoed upper end Martin Logan's multiple times and for acoustic music, vocals, piano they are fantastic and if I could own a second system I certainly would consider them.

But besides listening if you want to be scientific I suppose I would ask if someone doesn't think Harman International doesn't have the resources to test their speakers beyond that of most other companies?  I love little companies also (like Salk who makes a great speaker).  But to think the big boys don't have more testing resources is naive. 

Ultimately. Go listen and see what you think,

Actually, the big JBL is a wonderful speaker.....VPI uses it for the definitive test for their highest end turntables.