LCoS + Prism
Features: Cheap, small in size, small field of view, cannot be made into glasses due to obstructed line of sight.
Products: Google Glass, Vuzix M300.
Micro OLED + Freeform or Birdbath
Features: High contrast, high resolution, good color, large field of view, low power consumption, moderate size, can be made into glasses. Micro OLED has low brightness and low external light transmittance.
Products: Epson BT300, Rokid Glass, Nreal Light.
LCoS/DLP + Waveguide
Features: High brightness, large field of view, high resolution, high external light transmittance, wide range of applicability, moderate power consumption, very light and thin, can be made into glasses. Display color and contrast are slightly inferior.
Products: HoloLens, Rokid Vision.