My new ESP/950 from Koss have around 100 hours on them, and so far I think they definitely sound a bit better than my old set I sent in (when they didn't have the squeal). There is now semblance of a soundstage, and they sound great at rock and jazz. They are competitive with the HE60, especially given the price the Sennheiser's fetch.
Come on KG, we need a portable estat amp, I want to take these to work