When evaluating ECG recorders, you must prioritize signal accuracy and channel configuration. For clinical use, 12-lead systems are standard, while single-lead or 3-lead wearable devices are suitable for long-term monitoring. Ensure the device has a high sampling rate (at least 1000Hz) to capture subtle arrhythmias and features digital filtering technology to minimize baseline wander and muscle interference. Additionally, check for internal storage capacity and battery life, aiming for at least 24-72 hours of continuous recording for Holter-type devices.