Seen some tests on reddit that basically showed sonnet5.5 to be a wash. Half the cost but took twice as many tokens (and twice as long) as opus5.5. Probably depends on the complexity of the task, but if it's simple Haiku5.5 is probably better anyway. It's apparently super cheap under 100k context and you can tell claude to cap it there.
Also, lots of GPT resets this month while they try and distract from limit nerfing fyi.