Anthropic's "Max" modes are like a yolo mode. "use 10x the tokens to try to break the hardest possible problems". They're not less efficient at normal modes. Medium is their default.

I can't see Ember on AA's index yet, but their post claims "half the reasoning tokens for the same answers" as Kimi K3.

That would make it about so, I assume?

                 AA     Output  Reasoning  Cost / task
    Kimi K3 Max  44     48k     32k        $2.00
    Half tokens  44     32k     16k        ?

    Opus Med     51     26k     12k        $1.34
    Opus High    54     36k     18k        $1.82
    Opus Max     58     119k    84k        $5.98

    Sonnet Med   41     ?       ?          $0.59
    Sonnet High  47     ?       ?          $1.08
    Sonnet Max   56     193k    142k       $7.60