GaAs, GaN, and other gallium compounds are emerging as the key materials technology for the next 50 years of electronics. For electronic devices, if the first 50 years of the transistor were largely about silicon, the next 50 years will be about gallium. For other applications, gallium will also become increasingly important. 

There are many key attributes of the gallium that make it a far superior semiconductor. Among them is the far higher critical field limit (3*10^6 V/cm for GaN, versus 0.25*10^6 V / cm for Si), higher mobilities/velocities, higher frequency operation, better thermal conductivity and other parameters that permit far higher performance of resulting devices -- and circuits.  

There are many early products and exciting research in the GaN portion of the gallium revolution. 
International Rectifier's GaN product page
Cree's website 
TriQuint's GaN product page
RF Microdevices' product page