When evaluating air cushion soles, the most critical factor is the TPU (Thermoplastic Polyurethane) quality, as it determines the air bladder's durability and resistance to puncture. You should ensure the internal pressure ranges between 5-20 PSI depending on the intended footwear type (running vs. casual). Additionally, verify the bonding strength between the air unit and the midsole material (usually EVA or PU) to prevent delamination, and confirm a compression set of less than 10% after 100,000 cycles to ensure long-term shock absorption.