These headphones are amazing !!! I first got a pair of Grado RS1i's i was hooked at how amazing they sounded . listening to them on my ipod 5th gen (30g) & varoius portable amps (cmoy from ampedup 18v ra1 clone ,Fiio E07K amp , little bear b-1 portable mini tube)  .Wow , I must say the quality of sound was apparent right from the beginning . My first set of headphones Sennhieser HD 558 open back sounded great but still lacked something . the RS1i were amazing the exact sound i was looking for similar to listening to my home stereo (full sound ) , everything was there presence of low end (not over powering but there ) smooth silky smooth mids , and crystal clear highs  perfect !!!
So that's where i got curious as to how would the low end model of grado's sr80i sound ?? well I must say that they are just as amazing as the $700 RS1i's , more bass ,nice mids and clear highs . These are good headphones for just about all types of music . I must also say these sr80i's were used when i bought them ($65) , and beat up looking but the sound omg !!! soon after reading about modding on head-fi I decided to liberate and put these drivers in cherry-wood cups . They are more amazing now , tones that come from cherry-wood is awesome rival my RS1i's .
So to conclude I would say that for price compared to more expansive sennhieser HD-580 ($179) this is an amazing value sound and affordability wise ($99) .
Also upgraded to little dot 1+ tube amp and they are even more amazing both RS1i's and SR80i's highly recommend this amp (even the HD-580's too).