Buyers must prioritize waveform technology, specifically Biphasic Truncated Exponential (BTE), which is the current industry standard for efficacy and safety. Key metrics include energy range (typically 200J to 360J), charging time (ideally <10 seconds), and battery capacity, which should support at least 100-200 shocks or 4 hours of continuous monitoring. For AEDs (Automated External Defibrillators), ensure the device includes voice prompts and visual instructions in the target market's language.