I do like them alot, but members of head-fi seems to think very low of the HD 515. I'd love to get my hands on some Grado SR60/80s but I can't find any in canada! US stores that do international stores do not ship Grado elsewhere.
They're just pretty low in Senn's lineup, so they're not admired as much as the bigger brothers. I've listened to them a bit and they're a great budget set, a lot of the qualities of the HD555 for a lower price.