The key issue here though is that membrane technologies require an array of drive points which have inherent production cost issues. With regard to performance versus power or design considerations SLAB panels can be treated as conventional speakers. That is, when describing a 6W RMS satellite you will get equivalent sound pressure level from a cone or SLAB panel. SLAB speakers use a coil and magnet to excite the panel with equivalent impedance characteristics as cone drivers. Standard amplifiers need no special design considerations to drive SLAB speakers.
SLAB speakers have very low distortion properties.
Current SLAB models generate sound waves on one front panel with sound being heard both front and rear but the rear frequencies and volumes are different to the front output. So there you have it. Where the SLAB technology differs from the NXT technology is its more directional so in theory should provide better imaging for 3D audio. While it's more directional than NXT it still less directional than traditional cone based speakers and as an advantage offers a wider sound stage. The flat panels Monsoon uses is on the other end of the scale being very directional which is great for 3D audio but has the major disadvantage of the off axis performance being very poor.