What are the key differences between BJT and MOSFET amplifiers?

BJT amplifiers are current-controlled devices with higher transconductance (gm), lower input impedance, and better linearity at low frequencies. MOSFET amplifiers are voltage-controlled with extremely high input impedance, lower power consumption, and better high-frequency performance. BJTs are preferred for low-noise applications while MOSFETs dominate in digital and high-impedance circuits.