Hi mate.. HD800 + M-stage was my setup for more than 6 months and it was wonderful. I never thought that i needed an upgrade. The M-stage to me is less agressive in the highs and this is noticed especially when you increase the volume. It controls the highs beautifully and i found that it is a very good match with any bright headphones. Hope it helps.
2/20/12 at 5:38am