Robot dog or humanoid: how to actually decide

"Robot dog or humanoid" reads like a single question, and it is actually two: what does the floor allow, and what kind of payload figure does the job actually need.

The floor decides before the spec sheet does.

A wheeled platform like the G2 never has to solve balance, but it needs a flat, continuous surface and cannot manage a step. A legged platform, bipedal like the A2 Ultra or four-legged like the D1 Max, handles thresholds, ramps, gravel and stairs, and the D1 Max specifically crosses an 80 cm gap and climbs a 45-degree slope. If the site has a loading dock kerb, broken pavement, or stairs anywhere on the route, that alone rules out a wheeled platform regardless of what else it can do.

"Payload" means two different things depending which category is being compared.

A humanoid's published figure is almost always per arm: the G2 carries 5 kg per arm, the A2 Ultra about 2 kg per arm. A quadruped's published figure is a single total the platform carries as cargo: the D1 Max rated at 25 to 30 kg, the D1 Ultra at 5 kg total. Comparing a humanoid's per-arm number against a quadruped's total is comparing two different kinds of number, not two robots.

A humanoid handles a task; a quadruped covers a route.

The G2 and A2 Ultra are built for contact work at a bench or a shelf: manipulation, demonstration, service. The D1 series is built to move across a site others cannot reach with the same reliability, indoors or out, and carry something while doing it. Neither substitutes for the other's job description, which is why "which is more advanced" is the wrong question to ask.

Sealing and environment narrow it further inside each category.

The D1 Max is rated IP67 for genuinely wet or dusty outdoor work; the D1 Ultra is IP54, lighter duty. The G2 is IP42, indoor only, dust and dripping water rather than washdown. A route that goes outdoors in rain rules out the G2 the same way a step ruled out a wheeled platform in the first place.

Answer the floor question and the payload-type question before comparing anything else, because a robot dog and a humanoid solve different jobs on different terrain, not the same job at two price points.