Not discussing Mythos here, but Opus. Opus to me has been significantly better at SWE than GPT or Gemini - that gets me confused why Opus is ranking clearly lower than GPT, and even lower than Gemini.
Failed to use tools, failed to follow instructions, and then went into deranged loop mode.
Essentially, it's where it was 1.5 years ago when I tried it the last time.
It's honestly unbelievable how Google managed to fail so miserably at this.