Are electrostatics considered the next level with a corresponding price bump, or just an alternative technology?The latter.
One should be careful when driving ESLs if you wish to get the best out of them. Because they are a fundamentally different approach to transducers, the optimal way to drive them is different too. Most ESLs have an impedance curve that varies over a 10:1 or 9:1 range- the highest impedance being in the bass region, and then 1/9th or 1/10th of that at 20KHz. This is why Martin-Logans are only about 0.5ohms at 20KHz, since they are 4 ohms in the bass (which is often a cone driver).
Because of this impedance swing and because ESLs are based on a capacitor rather than a driver in a box, the usual voltage rules don't work so well on them. You can wind up with something that is really detailed and bright; what you are after is the former but not the latter. Now a speaker that is a driver in a box has an impedance curve that shows something about the resonance of that driver in the box- the impedance will be higher at those frequencies. ESLs simply don't work that way- the high impedance peak needs just as much power to make a certain sound pressure at 10 feet as it does at 1KHz where the impedance might be half of that of the bass. Conventional speakers don't work that way at all!
So if you are planning a solid state amp to audition the ESLs, be prepared for bright and weak bass. A tube amp is required to make the speaker play bass correctly, as with the higher impedances the amp can continue to make power where a solid state amp can't.
Its for this reason that on a set of Sound Labs you might need a 600 watt solid state amp to make enough sound pressure, but a 150 watt tube amp would be able to keep up with that 600 watt amp no worries! For more on how this works seehttp://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html
The advantage of ESLs over many other speakers is that they use a power supply to operate the electrostatic field. Conventional speakers that use a permanent magnet have a phenomena where as you put current through the voice coil, the magnetic field weakens slightly. This creates a slower and less dynamic result. The kind of permanent magnet driver that does this the least are those equipped with Alnico magnets, but Alnico is also the weakest magnet structure (although they can be focused nicely in the voice coil gap). ESLs don't have this issue and so they sound obviously faster right away. With conventional drivers the only equivalent that exists are field coil powered drivers, where a power supply supplies the energy for the magnet.