In general, results depend mainly on the physical size of the structure being tested. Larger structures are more robust than smaller structures.
Elements are also more sensitive than ICs.
Most ICs exhibit a damage threshold above 500 volts. The exceptions are ICs without protection circuitry which utilize special custom circuitry for absolutely optimum performance. In these sensitive devices, ESD thresholds were willingly sacrificed for premium performance. In contrast, some devices have minimum thresholds exceeding 1000 and even 2000 volts. If GaAs users are already employing precautions for CMOS device handling, there should be no additional requirements to accommodate GaAs devices.