Vibe Check: Sonnet 5, A Model Pitched for Everyone Impresses No One

The Goldilocks tier is the most dangerous place to sit in a three horse race, because it only works if nobody else is allowed to also be medium. Every's verdict matters less as a Sonnet review and more as an early signal that Anthropic's product ladder strategy, cheap fast Haiku, capable pricey Opus, balanced Sonnet in between, is getting squeezed as OpenAI and Google ship models that refuse to stay in their assigned lane. If the middle tier stops being a clear value proposition, expect Anthropic's pricing and naming strategy to shift again before the next major release.