- Identity
- Maker, model, generation, and the year it actually shipped rather than the year it was announced.
- Body
- Form, mass, reach or gait, degrees of freedom, payload, ingress rating.
- Brains
- Onboard compute, sensors, what runs locally and what needs the maker's cloud to work at all.
- Endurance
- Battery, real runtime under load, charge time, whether packs are swappable.
- Openness
- SDK, API, ROS support, licence, and whether a third party can still use it in five years.
- Price
- List price, what the accessories really cost, and any subscription attached to it.
- Living with it
- Noise, setup, repairability, spare parts, and the failure everyone reports.