Hey guys,been searching for a headphone/earphone to connect to my iPad/iPhone,a friend of mine suggested these two. My main usage is for music,mostly extreme metal which of course doesn't need a lot of bass.now I wanna know: 1. Which one will sound more clear when listening to highly distorted guitar riffs? 2. I've read that to tap IE80's full potential,you SHOULD have an amp,so if you use it without an amp,will it give you less sound quality than MM 550-X?what if used with an amp? 3. Which one's more comfortable when being used for hours? Also please share any information you think might be helpful. Thank you all.