Tried the Logitech Embody. Very nice chair, though only comfortable for up to around an hour for me. After this I had back/shoulder discomfort - not pain (I have no back or shoulder issues) but just an awareness that the plastic supports are there. Could also feel that some areas of the back rest had the extra padding while others didn't, it wasn't a smooth and symmetrical feeling. I felt my body was telling me that if I sat in this for a few months/years, I may develop back or shoulder pain, it did not feel good. The chair also got noticeably warm after an hour or so. I think I'm just too used to mesh chairs to be able to stand sitting in a padded foam chair all day.
Returned it and bought the Aeron remastered instead. I can sit in this for 12 hours (work & gaming/media after work) with no discomfort, no 'awareness' that I'm sitting in a chair, just a feeling like I'm floating and being fully supported while doing so. The arm rests are also much more comfortable. The chair is also silent, no squeaks no clicking. Of course being a mesh chair, this is lovely and cool to sit in, fully breathable which is amazing for our increasingly warm climate.
The forward tilt setting is also amazing, I use this when I'm "really" working, or if I'm working on an object/hobbycraft on my desk.
I’d HIGHLY recommend that anyone considering either the Embody or Aeron tries them out in a showroom. Unfortunately I could not find anywhere in Wales that had an Embody to try, so had to order it (and then return it).