I actually disageed with your con opinions.
 
The TH900's image is far better than many open back headphones, not far away comparing with HD800 as well. And I don't think it has any distortion on its "far ends of soundstage". (I actually not quite understand what you wanna explain tho...) 
 
I would recomend you to change your set up as TH900 can be easily driven by most, even portable amps. But that doesn't mean these amps are able to control the beast. If you have the chances, I would recomend you try some tubes or some of the well controled SS amps like P1u. 
 
Best Regards
Archer

got to agree with archeryc
 
i used my TH900 with many amps but the best were the WA7 with EH tubes, gave me a totally different sound than any other combo, even solid state amps.

^^^^ Irony!

I'll have to go back through it when I get back from work, I agree that there's some stuff that needs to be edited. This is why I was a CS major in college, I wouldn't last 5 minutes in an upper-level English class
 
Also, I think that listening to the HD800 earlier in the day may have influenced me, using this setup with the HD800 is pretty much perfect. Technically they're still in the break-in period. I probably shouldn't have been so hash on these cans, they really have a nice sound signature, and I should probably stress that a bit more in the review.
 
Also, I'm upgrading my amp to a Ragnarok, but that's a week or more away from getting shipped.