I have been spending a lot of time lately with the LCD-5. And let me start off this all my opinion and I am by no means a professional reviewer, simply an enthusiast.
I have several TOTL headphones, so have a pretty good reference point for where these stand among them. I am also fortunate enough to have 2 great systems in which I can compare them - both of which offer different experiences, much like each of my headphones. Additionally, I have a very average-sized head and have not experienced the comfort issues of others.
Let me start by saying I do not get all the criticism these are getting. They are not perfect, no headphone is. But, it is a highly enjoyable one. It really does scale with what you throw at it. I have fed it directly through the headphone inputs of my DAC's and while respectable, they were not able to provide them with the results I get feeding through a speaker/power amp. Now, this is very subjective, my amps will be very different from others. But with a respectable high-end gear chain, they really produce.
I recently came from the world of 2 channel audio and am relatively new to the Headphone/Headfi world. But I have over the years developed an appreciation for good-sounding gear. Again, subjective, good to me, maybe different than to others. I am in the more resolving camp of listening and haven't really explored tubes. So my experience lies in solid-state. That is not to say I don't appreciate musicality, but I am a stickler for detail.
Coming back to the LCD-5's they resolve incredibly. And for me, they sit right in the middle of the Susvara and 1266 TC's. And this is/was exactly the role I wanted them to play. Excellent bass and sub-bass presence, solid mids. But they need good amplification (which could be said of any headphone really - and good does not always mean power) and a good source (which again could be said of any headphone).
So, I might think that these headphones may show us the cracks in our chain, rather than themselves being faulty or inadequate. I want to spend more time with these to really appreciate them, but the first 2 weeks have been special. It has taken me a year with the Abyss 1266 TC's to really appreciate and tune them to fit my system, so I look to spending time with my LCD-5's and newly arrived Susvara's as well. This should be a practice with all headphones, before passing judgment - take your time. We need to adjust, process and take in the nuance, the newness of sound and appreciate the differences.
Thanks for listening to an old man rant. Appreciate everyone sharing in this and other forums.