Started off (and still own) the old green David Clarke 13.4. It does clamp on my head and hurt my ears after a full day of flying.
Now I use the Bose Aviation X (original version I believe), will never look back. Very comfortable and the noise cancelling is fantastic. I've had mine for almost 10yrs now and the after sale support from Bose was above and beyond. They fully refurbished it for me when it was well out of warranty. I won't hesitate to replace this with the A20 if/when the time calls for it.
Some mates have the Light speed equivalent and they seem to be happy as Larry too.