The ED9's take FOREVER to burn in, I would guesstimate 500+ hours. And, they need a crazy good amp, or they can indeed sound boomy and unnatural. Plus, the stock cable provided with the 9's, is, in a word, awful. So, I can understand where you are coming from.
Sennheiser had the HD800's driven by a Benchmark, which I am familiar with and the sound was very good. Heck, I was impressed enough with them to take 25+ pictures of them and tell anyone who would listen that they should go hear them. In fact, the DEQX guys who were sharing my demo room kept kidding me about my new "love affair" with the HD800's as I wouldn't shut up about them...

However, I, personally, hesitate to make any blanket statements about how good they are in absolute terms as I listened to them under unfamiliar circumstances, with a great deal of activity around me, so I need to hear them in quiet surroundings, driven by a truly *great* amp before I would say they are as good as a set R10's, HE90's, ED9's, or a top end Stax. I hope they are, I have pre-ordered a set...
Peace,
Lee
This is the first I've heard anyone compare the HD 800 to the ED9's. I've ordered the HD800 and would not be happy if they sound like the ED9, which I've owned. To me, the ED9's were unnatural sounding with an overemphasis in the bottom end. I've read that the HD 800 were closer to a Qualia 010 with more extension on the bottom end. They've been described as fast like you would expect from a e'stat headphone. A few have described them as perhaps the best headphone they've heard and this is coming from people that either own or have heard the Sennheiser HE90, Sony R10 and Sony Qualia. Don't get me wrong, we all hear different and like different things from our gear so I respect your findings. I just hope I don't have the same reaction. 