Familiarity. In the past I'd owned the HD580 and for a short time, the HD650 (when it was first introduced). At that time I believe I had an Eddie Current HD300, and I just didn't take to the sound of the 650 with the old drivers.
I still haven't experienced the current HD650, but am open to give it a try if my equipment combo seems to lean in its direction.
I guess you could say that I'm not looking much further than Sennheiser for classical music. In fact I may very well end up with a WA-5, at which point it would be an appropriate time to give the HD800 a try.
Edited by pigmode - 4/11/11 at 9:31pm