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

Tidal, Kharma, YG, Magico, Vivid G1, Grande Focal and German Physik
speakers are all mediocre IMO.
So is JBL.

JBL’s newest designs are the best value in audio right now, nothing comes even close.

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)