Electron mobility and drift velocity simulation results are presented for bulk GaSb based on a many-valley, anisotropic Monte Carlo model. Our mobility results at 300 K are in good agreement with available experimental data. Values close to the room temperature GaAs mobility have been predicted. Transient drift velocities are demonstrated to be higher than for GaAs and the negative differential velocity regime is shown to occur at much lower electric fields of about 1 kV/cm. The material could be useful as a low voltage oscillator or in high speed photodetection.