It does everything that the 990 pro does, but better. So yes, to me, it's worth the jump from the 990 Pro's price to the X1.
The standard K702 is a great headphone. I like the Annie because it has a warmer, fuller, more bassy sound. It's not that one is worse than the other. It's a different tonality based on the same sound. So you choose what you want more: A warm, rich, fuller sound, or a more analytical, and more spacious sound.
I have no heard the E10, but for music use, it should be fine for the X1, not the AKGs. The K70x demands and deserves a lot more power.
Edited by Mad Lust Envy - 8/4/13 at 12:56am