Claude Sonnet 4.6 vs Composer 2

Pick Claude Sonnet 4.6 if you want the stronger benchmark profile. Composer 2 only becomes the better choice if you want the cheaper token bill or you want the stronger reasoning-first profile.

Claude Sonnet 4.6 is clearly ahead on the provisional aggregate, 83 to 73. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Sonnet 4.6's sharpest advantage is in coding, where it averages 66.4 against 58. The single biggest benchmark swing on the page is SWE-Rebench, 60.7% to 58%.

Claude Sonnet 4.6 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.50 input / $2.50 output per 1M tokens for Composer 2. That is roughly 6.0x on output cost alone. Composer 2 is the reasoning model in the pair, while Claude Sonnet 4.6 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.