I have heard Stax electrostatic headphones from a foreign friend 2 years ago.
Most electrostatic headphones like Stax and the top AKG require significantly more amplification than your standard voice-coil driven headphones because electrostats need to be energized by electricity in order to move; think of how an electromagnet works. Think of them miniature electrostat speakers rather than just headphones; You will need a head phone amp to power them, and they take considerable time to break-in.
In terms of comfort, these things feel like ear warmers because they literally get warm as you use them (i'm not sure about the newer models though). You may not like the sensation. Stax head bands are also very stiff and uncomfortable.
In terms of sound, These type of headphones compromise warmth, weight, and euphonics for the detail and accuracy. They are more analytical than enjoyable.
They will provide superior transient response and transparency compared to conventional headphones. This may be perceived as brightness by some. In terms of bass, its bass is too lean for my taste.