That was me.
Overall it is just my personal opinion. What I personally like might not be the universal answer to the question which headphone is better.
I tried both lcd2 and x in their pre and postrevamp versions. Pre revamp i liked the LCD X more, they sounded more open, detailed and had a harder slam than the lcd2. This was at a local shop A/B´ing both.
Fast forward I am owning the LCDX (2016 driver) and LCD2 (was built 2017). Regarding those two cans, the LCD2 has a wider soundstage, VERY fast clean bass (almost unrealisticly so), sounds more transparent and the overall timbre is more natural. In general it tends to sound a bit brighter than the new X.
The X sounds a bit darker, less transparent, more congested, less lifelike in timbre. The only things the X does better: Bass is still a bit stronger and more bloomy and the imaging more precise. But this is just comparing the 2016revisions of those headphones.
Overall the old LCDX was the best headphone out of the 4. They combined the clarity of the new lcd2 with a wide soundstage, full sound and a bass that was absolutely lovely. The 2016model seems bass light in comparison (even tho stronger than the LCD2 as i mentioned).
Just my 50Cent
But i suggest to audition them yourself and report back here after doing so.
greetings