Qwen3.8 125B (6B active) Flash-Next

User compares Flash-Next against a dense 27B model. Flash-Next is faster and mechanically flawless, with zero failures on strict JSON, injection resistance and SLAs, and wins the high-reasoning spatial and code-gen tier with better failure modes. The dense 27B still wins sustained multi-step symbolic work such as bug-fixing, math proofs and abstract puzzles. On that symbolic work Flash-Next shows a new failure shape: it promises the deliverable, declares "done", and outputs nothing. Both models use the same reasoning_effort knob with radically different semantics, so Flash-Next is not a drop-in replacement but a conditional promotion.