I have tried out grok 4.5 quite extensively on
@cursor_ai in a given repository where I also tested Fable, Opus 4.8 thinking high, 4.8 thinking-high-fast, GPT 5.5 and Composer 2.5 Fast.
It was surprising to see that after multiple test runs,looking at the output tokens per dollar :
claude-opus-4-8-thinking-high: ~3,245 tok/$ (44,426 output tokens for $13.69)
grok-4.5-fast-high: ~2,955 tok/$ (15,427 output tokens for $5.22)
So Opus wins by about 10% on output efficiency.
While performance is quite similar in both.
Not quite sure, if the benchmarks are slightly different, but for my usecase both Opus 4.8 and Grok are almost similar in both performance and pricing. Grok is not really an improvement in terms of cost.
Takeaways:
composer-2.5-fast is the clear winner — most output tokens for the lowest cost (~7,182 tokens/$).
claude-opus-4-8-thinking-high is the best value among the Claude/high-reasoning tier (~3,902 tokens/$) and produced high output volume.
grok-4.5-fast-high and gpt-5.5-high sit in the middle.
claude-fable-5-thinking-high and claude-opus-4-8-thinking-high-fast are the least efficient (~605 and ~752 tokens/$) — highest cost paired with the lowest output.
P.S. this is just a personal run, and output might be different for others.