I bought 2 of these without any tryout, only based on Youtube comparisons with a studio headphone (included in the Focusrite studio set).
I am very satisfied with the sound and the stereo imaging of the speakers, actually I love just to hear music on them, not just for studio work.
Many of reviews were about lack of bass, but even for just listening to music (pop, rock, metal, southern rock, modern metal etc, blues, jazz), there is enough bass I can confirm that.
For my taste these speakers are very natural sounding, round and the notes are very understandable. Hearing them from 0.5-1m, the result is perfect.
I have currently no time to make music on them, but I can imagine full mixing and mastering processing on these ones. Of course for super-lows mix I would prefer a good studio headphone, and at the finalisation hearing your music on different speakers and headphones is always a great practice. For D4 version I suggest to add a high freqency booster potmeter.
I recommend these ones, they are loud and great!
After two years: Finally after 2 years I found the highs rolled off too much, it is easy to
make too crisp/harsh mixes on them. I found my mixes became too warm sounding
not enough aggresive on them. With the acoustic space to -4db and cross reference
with a great studio headphone (like ath m40x) the results can be much better. Stereo imaging, amount of bass is ok. For less agressive styles it can be a good monitor.