Hm, I think the 7550 is most likely the best one, but this is all talking from my Teclasts. If I could compare all four (four including the EX700) at home, then that would be another story, but I believe Romy has already half-written that story so I don't care. The EX700 is still the best one to me. When I listen to it from my favorite desktop DAC and amp setup, it's incredulous.
It feels like... http://www.youtube.com/watch?v=A5In5ppfcTE#t=4m36s