Pick a winner in each dimension — change your vote anytime.
Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).
Choose GPT-5.5 if you want hard reasoning and coding for teams in the OpenAI ecosystem. Choose Grok 4.20 if you want agents that genuinely need 2M tokens of context.
In our editorial scoring, GPT-5.5 leads in 3 of five dimensions (output quality, agentic ability and reliability), while Grok 4.20 leads in 2. On price, GPT-5.5 runs about $13 per 1M tokens (blended) and is proprietary; Grok 4.20 is about $1.63 and proprietary.
The model picks the moves; the agent runs the loop, the tools, and the guardrails. Once you've chosen a model, see which agent gets the most out of it.