Claude Sonnet 5 Review: A Week With Anthropic's New Default
Claude Sonnet 5 review after a week: it nearly matches Opus 4.8 on coding, beats it on Terminal-Bench, and runs at just $2/$10 — but the tokenizer bites.
Claude Sonnet 5 review after a week: it nearly matches Opus 4.8 on coding, beats it on Terminal-Bench, and runs at just $2/$10 — but the tokenizer bites.
Qwen 3.7 Max costs $7.50/M output vs Claude's $25. But it generates 4x more tokens per task. Full benchmark, cost-per-task math, and who wins for what.
GLM-5.2 scores 62.1 on SWE-bench Pro vs GPT-5.5's 58.6, ships under MIT, and costs $1.40/M input tokens. Benchmarks, pricing, and the China data question.
GPT-5.5 hits 82.7% on Terminal-Bench and uses 72% fewer tokens than Claude — but loses SWE-Bench Pro to Opus 4.7. Seven weeks of real agentic use, reviewed.
Claude Fable 5 hits 80.3% SWE-bench Pro and 29.3% FrontierCode Diamond. It also costs 2x Opus 4.8, retains your data 30 days, and silently falls back.
Three weeks rotating between GPT-5.4, Claude Opus 4.7, and Gemini 3.1 Pro on real coding work — benchmarks, token costs, and the per-task winner for each.