For the last 2 years I've been on a bit of a quest to find an upgrade to my HD800S + EQ to the Harman target.
So I think I can be of some help. All my impressions below are subjective. I'm 35 so I don't think I'm deaf yet
All comparisons below are with both headphones EQed to the Harman Target.
First I bought an LCD4, sent it to Austria to be measured and EQed to the Harman Target.
LCD4 with EQ was a marvellous headphone with better bass and ''perceived impact'' than the HD800S. So I sold the HD800S.
Then I bought a Focal Utopia and again EQed it to the Harman Target. I felt like the Utopia had slightly better clarity and imaging but the LCD4 has better bass for modern music.
What kind of music do you listen to? I think this is an important factor.
If you listen to a lot of classical, female vocals, folk, ''audiophile'' type music I think the Focal Utopia could be a contender.
If you listen to a good mix like hard rock, rap, EDM + everything mentioned above the LCD4 is a better all rounder IMHO.
Please note that going from the super comfy HD800S to the 700+ gram LCD4 may be quite an adjustment. The LCD4 was ok for me up to 60 minutes. My listening sessions are usually around an hour so this was not issue for me.
My current set up: Mjolnir Audio KGSSHV Carbon amp + SR009S (Again EQed to Harman target):
For me this system slightly beats the HD800S for classical, female vocals, folk, ''audiophile'' type music which is what I gravitate towards during my late night listening sessions (the only time I get to focus on listening to music in peace)
With the Stax system you get a slightly less impactful bass but you get very good clarity, vocals that sound beautiful and picking out each instrument in the mix is very easy.
Unlike most audio reviewers I don't gush over any headphone based on price. IMHO my Stax system is about 5% to 10% better than my HD800S. It also cost me 7 times more. I had the spare cash so I was willing to splurge for that tiny bit of extra performance.
If money is not an issue I would simply buy the Utopia, LCD4 & a Stax system and keep your favourite.
If you don't want to deal with all that hassle my recommendation is the Stax SR009S with EQ. It takes the best qualities of the HD800S just a bit further. Except soundstage. I think the HD800S still has the slightly better soundstage.
Hope that helped.