Comfort is in the head of the wearer and I've had no problems with these. I did have a big problem with the LCD 3 headband to the point I couldn't wear them for more than about 20 minutes before I got a very painful spot. I suspect head shape affects comfort more than size because I have a pretty large noggin.
IMO, amps don't make a lot of difference except in volume attainability.
I could not disagree more, I noticed a huge improvement in going to tube amps. Using the AudioGd 11.32 onboard amp the phones exhibited a dry, harsh, grainy, & fatiguing signature, switching to using the onboard DAC through my tube amp all the above was reversed
This of course has nothing to do with the HE500 except that it plays what is put into it rather truthfully. It will reveal amp shortcomings