LOL. YouTube reviewers. I see what's going on here.
If one wants "technicalities", sure HD800 trumps all, but get a (A grade) Clear on a synergetic amp / dac combo, and it easily plays in the same league as an HD800 from a great matching tube amp, minus obviously the famous HD800 "liquidity" and "wow" wide staging factors. Clear wins in the "master of non, jack of all" category, it's just way more balanced and sounds always right, dynamic and fun with any record. I really can't point on any lack of detail in the Clear vs the HD800. And also, unlike the HD800, the Clear have "punch". The HD800 in comparison are simply too muted or light in the lower harmonics regardless of EQ or tubes or whatever. I'm pretty sure the Clear wins in full audio spectrum dynamics while the HD800 may be more technically capable in higher mids and treble harmonics resolve but at cost of sounding light/muted in lower harmonics. As for which one can be made to sound better with EQ, well let's just say I never succeeded in EQ-ing the HD800 to sound as good overall as the Clear sound without any EQ, must be that Focal "punch" and dynamics that does it for me, idk.
Still, the HD800 are regarded as the best for what they do, and have a different purpose in one's head-fi setup than the Clear usually have. Used with a dedicated setup (most often tubes) and a complementary headphone setup, usually planar magnetic. At least that's my case.