Buyers should prioritize Degrees of Freedom (DoF), which determines the fluidity of movement; high-end models typically feature 20-50 DoF in the face and limbs. Ensure the actuators are brushless DC motors for longevity and quiet operation. For the AI component, verify the Natural Language Processing (NLP) capabilities, specifically support for multi-language interaction and low-latency response times (<2 seconds). Additionally, the skin material should be medical-grade platinum silicone for a realistic tactile feel and durability against tearing.