I am not native english speaker but the word that instantly popped in my mind when you asked me to describe how I feel about HE 560 is "meh".I didnt compare the headphones too much,I dislike their sound so much I put the down after minute or two they all bore me except Edition X mkii which was like skynet robot drilling into my brain with ultrasonic scalpel.
The edition X had worst treble I ever heard in my life,some headphones have frequency response problems,specificaly sharp peaks and holes,some have resonance problems... ringing! Others have distortion problems,the Edition X had it all in treble.No headphone is perfect,even new HD650 have peak from 11-15KHz,I can enjoy imperfect headphone but Edition X,thats just ridiculous,the treble had such a nasty,very high,very sharp peak that was both ringing strongly and very distorted at the same time,it stuck out like sore thumb,I was not able to ignore it even for second.
It had little wider soundstage and little better comfort than HE400i,560 & Sundara but its treble was simply 100% pure ,multiply filtered,distilled cancer.Before,I used to think HD800 was most harsh treble in world of high end headphones,I was very wrong.I read so much good thing about it,I was extremly dissapointed.
One thing that HE 560,Edition X mkii and Sundara did well was bass,it was flat and extended,very nice,I liked that.I also liked that they all had bigger space for ears in the earpads,comfort was good in HE 560 and Edition X,weight no problem,headband works fine,earpads not itchy and space was good,I have 6.2mm high ears.The edition X had most space,least ear touching but I found the shape of the cups and pads little too long verticaly,also the pads were tiny bit too thin,I liked the Sundara pads more,but Sundara had less space inside them.
Now comes the revelation,I strongly prefered the HE400i to all the other Hifimans,the treble was least problematic,its only Hifiman headphone I enjoyed.The pads were lesser quality than Sundara,but it was light comfortable and bass,mids and highs had pleasing balance to them,I enjoy these without mods or EQ.
HE400i didnt had Hd650 resolution or the smoothness of frequency response,there were dips and hills in FR,but they sounded like small,smoothly transitioning peaks and holes,no audible distortion or ringing,I actually liked them,not as much as HD600/650 but alot more than Edition X or even Sundara.
In my opinion Hifiman headphones have zero relationship between price and sound quality,I would rather buy HE400i even if Edition X or Sundara was cheaper.It wasnt neutral,but its signature sound was pleasing and fun.The pads were kind of cheap and little itchy feeling,would definately buy some better pads.
Ohh and the 400s,it sounded second best,but it was like weak,cheap,downgraded HE400i,nothing much different,just the frequency response gave it limp wristed weak thin sound,otherwise its same thing as 400i.Someome might like that sort of sound,not me,but it didnt had any obvious problem,it wasnt neuron ablating pulse laser of death like Edition X.