Characteristics of GaAs photoconductive semiconductor switches (PCSS) during the initiation and sustaining phases of high gain switching are studied in this paper. Infrared electro-photo luminescence data are present which show current filaments during high gain switching mode. Triggering of these devices with multiple fiber optics is demonstrated and the implications for high average current density switching are discussed. Switch jitter with high field lateral PCSS has been tested and its impact on multiswitch systems is explored. Results from high repetition rate device lifetime testing are also reported. Lateral switches with several types of contacts (including: refractory metallizations, diffused and ion-implanted Ohmic layers) have been fabricated and tested. Switch characteristics and lifetime results will be discussed for each of these fabrication schemes.